+1 for Majorca - been there many times and it never gets old
Gran Canaria was awesome (and cheap)
The Lake District in England is also spectacular although majority of the climbs are shorter (and often steeper) than those longer steadier ones found in places like the Canaries / Mediterranean islands or the French / Swiss Alps.
Enjoy your trip wherever you select 
Early June is still very much spring. Pick something where you donāt have to pack a thousand āmaybeā clothes, and maybe just need a lightweight wind jacket. "just in caseā stuff means over packing and carrying a lot of stuff with you.
Iād recommend some place itās easy to find food/water as youāre riding. If you get too adventurous, youāre 30mi from a town and out of water. Also pick a place where you know youāll be exploring and when youāre not exploring. Hiring a guide (guide or kid from a local bike shop) isnāt a bad idea even if the location is pretty approachable. Also, keep in mind that youāre only biking x hours /day, youāre chilling the rest. Itās better to dip your toe into adventuring with a group then it is to go full Laos.
Recommendationsā¦ remember you donāt travel to France, you donāt travel to Paris, you travel to a particular part of Paris - you can go to that spot in Paris and never see āFranceā. I never biked there, but northern Italy based out of Florence. Have someone drive you out (or train) to somewhere everyday and ride back to the hub. You can hit the Cinque Terra, Sienna/"Tuscany, a finger lakes day (keep the main room in Florence and an overnight room at the daytrip for showers), etc. That gives you ocean, hills, weather, flats, and some convenience - more variety is better than less variety. Maybe pick another and youāve got a full trip.
Ignoring the cycling portion of the question, if its your first time in Europe try and visit Rome and Paris.
Really? Rome is one my all time travel let downs. Been there twice, checked out of my hotel two days early both times. You see the Vatican, the forum,ā¦ and pretty quickly youāre looking at yet another church and god statue. The eateries arenāt plentiful, the neighborhoods arenāt fun to exploreā¦there are better places to be. For urban Western Europe - Berlin, Paris, London, Amsterdam, and Barcelona are legit. Rome is up there with Brussels, Frankfurt, and some airport corridors.
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Actually, that would be a GREAT tripā¦ get a Europass, explore the city one day by bike, go for a big ride the next, train ride to the next town, and repeat.
Weather in Ireland. Like the UK, is pretty unpredictable.
One of the reasons I think the wicklow mountains is great for cycling is simply because itās quiet of cars and people and 10-15km from a capital city! There is even great mountain bike trails all over. Other places in the south of Ireland (dingle/kilarney) may be more interesting as a cycle holiday.
Although I must say when bikepacking across Wales though the most rural paved route I could weave together, I had a similar connection for cycling there too! Scotland, also not far off in terrain, is hooching with midges in the fairer months.
Definately give it a look into!
Yeah I agree the Europass idea sounds great! Only thing Iād be worried about is housing. I was thinking hostels but that wouldnāt be safe with bikes right? Other than that just hotels and Airbnbās?
Hostel wouldnāt have enough space to unbox your bike and store the case. Airbnb / VRBO here. Sample $74/night with washer/dryer https://www.airbnb.com/rooms/32764347?adults=4&location=Florence%2C%20Italy&check_in=2022-03-27&check_out=2022-04-03&translate_ugc=false&source_impression_id=p3_1634478473_l6PlwyODk81yiUBp&guests=1
Iād skip Tenerife because it looks like Zwift island
+1 for Tenerife
YouTuber PeakTorque has high praise for Greece, I personally havenāt been there, but may be worth checking out. Check his YouTube channel for details.
Iāve been to Greece a few times. Both to the mainland and the many islands. I wouldnāt cycle there.
Slovenia. Check out the Tour of Slovenia. A beautiful cycling country.
Same here. Many roads are terrible, traffic is wild, and there isnāt much of a cycling culture.
Many many Mediterranean countries Iād prefer to Greece.
I go to Greece regularly for cycling.
Highly recommend the Peloponnese for cycling. Great roads, wonderful terrain, amazing food and people. Iāve never had a sketchy moment with a driver passing too close or doing some asshole maneuver - and Iāve been quite a few times. Iād definitely avoid the big cities and would absolutely recommend you check out the areas around Kalamata.
Whistler.
That time of year, southern Spain or Southern France. Hands down. Great good. Excellent riding. Superb riding.
A few cycling destinations that have been recommended to, but I have never been there:
Most hostels in Europe have bike sheds.
Regarding bike box, you could use a cardboard box, get rid of it at your destination, and geta new one before you fly back.
To be honest, Iād go on youtube and watch where other people are riding, and then go whereever looks good to you. Other than that, you might need to think about what you want out of the trip - experience (road) cycling culture? See something new with some cycling thrown in? Amazing scenery? Somewhere remote, where others donāt go?
Has anyone been to Mallorja / Tenerife in December or over Christmas? Iām considering a 4 day break and would love to hear about experiences and opinions.
Yes Iāve been to Tenerife in December. We went for a 3 week cycling holiday. The first day we went out Teide was closed near the top with snow but it was cleared and open the next day. The locals were all up at the top of teide snowboarding.
Weather was pretty good all 3 weeks.
If you have any questions ask away.
I donāt have any advice for cycling destinations. Back when I did all my traveling I wasnāt athletic, so I missed out on a lot of the stuff I love now. But to go along with what BBarrera said (as I donāt do bars or anything like that):
One thing about placed like Europe, history is EVERYWHERE. Not something like in America where we see a 150 year old something and think āOh wow, thatās amazing!ā. I canāt remember what town we were in, near Lorient France, where we (my ex wife and I) realized we walked through old gates like you would see in a medieval movie, walking into the castle walls, and the town just continues on inside. Old buildings that looked to be 1000 years old with satellite cable dishes on the roof. So much history around you everywhere that the locals just donāt even think about it, but amazes people like me. I didnāt even get the chance to see the WWII sub base.
Also, seeing the colosseum in Rome and Pompeii were both childhood dreams fulfilled. I would love to go back and visit again.
A lot of pros in the off season head to the Costa Blanca in Spain (first time I went it was the Denia area). Iāve only been once but I can see why. I was supposed to go back with my club mates from up north when this wee c thing hit; they are talking about reorganising there (Calpe) or Mallorca; I hope the majority votes for Calpe in the Costa Blanca. Iāve done Mallorca a few times and my memory still prefers the Costa Blanca. In the meantime Tenerife is probably my next destination.
My mates round here tend to go to Oudenarde, Belgium probably as its easy for us to get to, if you like Flandrian stuff its good, but less off season weather reliability. Ive done the Alps once with them too, but it not so easy for us to get too and its also weather dependant but if you are a climber its ace.
Any of the European classics except for France - Accommodation, food and drink are far better quality for the same cost everywhere else.