Hawaii ride suggestions (big island)

I’m headed over to the Big Island for a week Feb 18th, and am looking for ideas on routes/rides for myself and my partner. We will have bikes Feb 20-23. We are looking for flat rides (for the two of us), and a longer more difficult ride with a bit more elevation Saturday and Sunday morning (just for myself). We are staying at the Fairmont Orchid close to Waikoloa Village. I’m from the prairies, so climbs/descents are definitely not my strong suit, but would like to get a bit of experience. I am finishing SSBMVII for the second time in a row, so have a bit of fitness coming in. Thoughts/suggestions?

Highway 19 is the Queen K highway - the Ironman bike route. Ride north to Hawi, ride south to Kailua-Kona. Very windy in the afternoon. We’ve ridden Hwy 19 up to Waimea, but it was a long time ago and can’t vouch for current conditions.