I agree with Catra about propping on the underseat stowed bag and do the same thing. I am pretty short though. Getting a seat with the 4 inches extra leg room may make this easier for you Spike.
This summer I am going to be on a very long flight. I booked bulkhead and plan to take my little three legged collapsible camp stool to elevate on. So long as the fasten seat belts sign isn't on I don't think it will be a problem. Last long flight I pulled my rolling backpack out and propped on it in the bulkhead. This helped absorb some vibration too....
I can say as a Texan, that heat can definitely be a problem. Although we do have more humidity here. Budgeting in for extra AC you may want to run and making sure your apartment, condo, community has a pool will make those long hot months more tolerable. Believe me 3 months at over a 100 degree temps do feel quite long. Not that I would trade it for ya'lls winter....