With most 5er's a one ton diesel either single or dual will handle the loads of all but the heaviest.
You haven't said what experience you have in towing. Have you ever towed anything close to that size? It's not necessary but a few years experience in towing stuff makes a world of difference in how you look at the trailers and trucks.
Also would ask if you have had any type of RV in the past,
What type of camping are you intending to do? Resorts, BLM, there are a lot of differences. Genny qx makes it appear you may be thinking boondocking if so, tank sizes become an issue so look to those.
If towing will be a new thing for you, I'd suggest a one ton diesel with at least a 6.5 bed and get a used 5er smaller than what you mentioned and spend a year travelling with it, become accustomed to towing and then decide on a nicer one to keep long term.