I made the mistake of believing post on here that 36 feet was the max for national parks. Did not that long to realize that is BS so traded for a 40' DP. Once we could use a MH more than 100 days/year found current rig slightly used and that was 13 years ago. We are half timers which works well for us and yes a DP is the nicest way to see the USA and the most expensive way.
Since you are keeping the house I would try it in your 5er as 24/7 in 1/10th the space takes some adjustment. Instead of larger axles leave stuff home and do three months trips coming back home to TX for a month and then off again. If after 8-10 months it's going well then a DP.