Acclimising yourself to elevation is not a deal breaker, just take it easy for the first couple days, and take along (and drink) plenty of water You can always dispel it when you need to!
The idea of Jackson is great, as long as you understand the "tourist-trap" mentality in Jackson. Its a nice town! I don't know if you even WANT to circumvent around Yellowstone. Its so georgeous, just alot of traffic. Try the ideas put forth in the above reply, just make sure you leave time to be a tourist. Oh, and also DO NOT miss spending awhile in Grand Teton NP, the views are killer