FWIW, I LOVE my SL7. However, it is easily the most surface sensitive bike I’ve ever ridden - I feel every pebble on my rides. Chip and Seal is brutal. And this is with running low 70s PSI and pretty thick supacaz bar tape.
YMMV, but it wouldn’t be my go-to if vibrations are an issue.
Enve Melee? Aero, pretty light, and can accept up to 35mm tires which will probably have the most impact on making a supple ride. Haven’t ridden one yet, but the reviews seem solid. Could be an issue trying to track one down for a test ride. Also agree with the aethos comments, that bike is really compliant over rough surfaces.
I’m of the opinion that tire choice/setup will make more difference than bike choice. Largest tires for the application, lowest pressure possible. Running 20 less psi is going to make way more difference that picking the squishiest of 40 different rigid frames.
That’s not to say you cant do both of course…but the frame is the wrong place to start ‘solving’ a vibration problem IMo.
Agreed
To the OP, what size Caledonia does she have and how many spacers is she running? Some of those bikes have a stack that is quite a bit lower
Buy an isospeed decoupler doane. Light, comfortable, fits 30c.
Or just get a gravel bike and roll around on 40c slicks.
The Domane is the road bike with IsoSpeed. It also allows for 38mm tires, so it can be quite plush.
However, for a bike without suspension and a bit of aero shaping, the 3rd gen Emonda is a very comforting riding bike.
I’m thinking if the caledonia feels too heavy and slow, it’s going to be very difficult to get something lighter and as comfortable - given you’ve already said it’s a good fit. Comfort is really about larger volume tires, which adds weight and won’t be as aero.
i just want to add the quality a good set of carbon wheels with supple tires does for smoothing out the ride quality. I have a pair of dt swiss aluminum rims set up tubeless with a not great 30c tire that measures 31.5 versus a pair of old flo45 disc wheels with 25c gp5000 tubed on them. The flo wheelset are remarkably smoother than the wider tubeless wheelset. I’ve even tried the flos with not supple 28c specialized roubaix tires and the more supple gp5000 though narrower are still a smoother/better ride. And the leaf spring effect from a deepish section carbon rim does make a bit of difference as well versus a shallower rim be it carbon or aluminum. I have a new pair of FFWD wheels waiting for good weather that are 44 deep and will be run tubeless with a 28c race tire. The already smooth ride of my Litespeed ultimate is about to become the smoothest ever.
What you need to do is use elastomers like the eesilk seatpost and stem, or redshift stem. That and tubeless tires at moderate pressures.
Yea that’s the nuclear option haha, you’re not going to get softer than 40c at like 25-30psi. But theres a lot of room to play with a proper road setup. Tubeless 28-30mm tires, run 50-60psi, that will probably be dramatically more comfortable than any 25mm tire setup she’s tried.
Also…obviously I’m going off of limited information…but the Caledonia probably came with gravel tires at 35mm+. If those are still on there…I’ve noticed once you go past about 30mm the bike starts to feel less like a road bike with how it turns/handles…it feel less nimble. This could be impacting how the bike ‘feels’ weight wise.
If it were me…on the assumption there are gravel tires on there…drop psi down to 25 or 30, see if the comfort is good. If it IS, throw some 28-30mm tires on at low pressure, and the problem may be solved all the way around.
Not that I want to talk anyone out of a new bike, mind you 
Wow the domane can take 38mm tires?? Newer bike tire clearances never cease to amaze me. One of these days I’ll get a road bike with bigger clearance as a do everything cross/crit/gravel bike.
Yeah. Unless you’re riding a lot of hills and mountains, my opinion is that wheel set and tire choice will make the biggest difference in how fast it feels to her.
I bought my wife a domane and while there’s not a lot of clearance around the tire it can actually fit a 40c. I put a kenda booster in the rear triangle with the only concern being mud clearance.
Yup, they made it quite capable and a bike that can edge quite close to a “road/gravel” bike for some use cases. FYI, Trek is great in that they list the max tire size in the specs section for all the bikes I’ve ever checked on their site. Worth a look anytime to see what each offers.
Yea that’s perfect for me. 40mm for dry gravel races (I’m not going 60+ miles in rain and mud lol), 33mm for cross races with plenty of mud clearance
Find a Parlee, easily the smoothest riding bike I have ever been on.
My friend’s 5 year old daughter has a pink bike with unicorns on it. Not sure if that is of any help?
Not on your list, but I have the new Emonda SLR 9 and I’ve been super pleased! I highly recommend testing riding one if possible. The weight is impressive for disc and 28mm tires, but the ride quality is what really stands out. The power transfer is the best I’ve felt and it still is pretty darn compliant for a race bike. It may not be the most aero compared to a true aero bike, but it’s the most aero the Emonda has been. Good luck!
thanks for all the input. info overload 
but that’s the beauty of the forum. will sift through all this over the weekend