Here is what I found on your vehicle for towing:
A 5.3 V8 is standard on Yukon XL and optional on Yukon. Both Denalis and the Yukon XL 2500 come with a 6.0-liter V8. An 8.1-liter V8 is optional for the Yukon XL 2500. All have an automatic transmission with GM's Tow/Haul mode; it gets revisions for 2002 designed to improve durability. Maximum towing capacity is 8100 lb on Yukon, 12,000 on Yukon XL 2500.
Here are the rating on the Windjammer:
Dry Hitch Weight 877 lb. (398 kg )
Dry Ship Weight 6,948 lb. (3,152 kg )
GVWR 8,550 lb. (3,878 kg )
Cargo Carrying Capacity 1,602 lb. (727 kg )
Exterior Length 34 ft. 5 in. (10.5 m)
Exterior Height 10 ft. 0 in. (3.0 m)
Exterior Width 96 in. (2.4 m)
Fresh Water Capacity 43 gal. (163 L)
Gray Water Capacity 38 gal. (144 L)
Black Water Capacity 38 gal. (144 L)
Awning Size 20 ft. (6.1 m)
If you have the Yukon XL 2500 it looks like you would be okay. I have the V-Lite 30WTBS which has the quad bunks and a little less hitch weight than yours due to no outside front kitchen. We needed the extra bed more than the kitchen and less weight was a bonus for us.
YOu will not be disappointed with the Windjammer. I've done a ton of research on the TT with bunks as others on here have already said and the Windjammer/V-Lites are top notch and there is nothing out there better. The only other TT that we debated was the Rockwood 8311SS but the master bedroom in the back on the V-Lite sold us! Tons of room.
Do your research and you will come back to the Windjammer/V-Lite IMHO. (In my humble opinion). If you have more precise questions let me know. I visited the factory where these trailers are made to watch the building process. It was very impressive. Good luck and enjoy the buying process.
Final words: Please take Kamp K's advise and make sure your tow vehicle will take the weight of your trailer okay. Look in your owners manuel and check what the WDH MAX hitch weight is. Yours will be well over 900 and close to 1000lbs once loaded with battery, propane, etc...
If it looks like your going to be too close on the hitch weight another option could be the Windjammer 3006W which takes away the outside kitchen and adds another bunk bed and more storage. Which is the one I have in its twin sister the Flagstaff V-Lite.
Sorry for going so long.
Philip, DW, 3 DD, 1 DS, and Kadie our Dog
2013 Flagstaff V-Lite 30WTBS
2003 Ford Expedition 5.4 Liter with 3.73 Axle
Equalizer 4-Point Sway 12000# & Tekonsha P3
48 Days of Camping Reserved for 2012