Welcome to Sunline Owners Club and congrats on your new coach!
If the bearings where packed correctly when it started to sit, odds are better in your favor. You may end up fighting a frozen brake more so then the bearings. The frozen brake may be more that it just plain will not work verses frozen stuck on but anything is possible. If it is stuck on, try backing up it might release. My son bought a used pop up, a 98 and he towed it to my house from the dealer about 50 miles away. The 1st thing we did was pull the wheels and drums. The grease was hard but not brittle hard thank goodness. Have no idea when the last repack was but by the looks of it I would say ~ 6 to 8 years maybe some more.
Having moved trucks and open trailers that sat for years out in the weather, some 20 plus years, as long as they had a good quantity of grease in the bearings the odds where better.
Stopping and checking for heat is a good prudent measure. You will get some heat but it spit fries that is way too hot and axle damage may come soon after. If you can hold your hand on the hubs it is not too hot. Be careful and "feel" for heat. Meaning rest your hand about 1/2" away and feel for radiant heat before touching. It if is really hot you will feel it 1/2" away. Ideally a infrared heat gun if you have one or a surface thermomter but feeling for heat works too just fine in this case.
The best thing you can do is go slow. 30mpg to 40 mpg is plenty and approaching 50 - 55 might be pushing your luck too far until you know what is inside.
I'm making a wild assumption the tires may be over 10 years old too. Pump them up close to max side wall cold pressure before heading out on the road. Riding them soft being old will create an issue real quick.
Once you get it home, go through the entire running gear and new tires will need to be in there too.
The good news this is not a boat trailer that has not been towed for 10 years. That can be more of a free for all dealing with the submersion of the trailer and not knowing how filled the cavity was. Did some of them for the Boy Scouts and it's a wonder they did not disintegrate by the time I made it to the house. I think what saved them was the sail boat was so light we did not have a lot of weight to deal with.
Good luck and looking forward to hearing and seeing more about your Sunline camper and camping adventures. Yes we like pic's!!
Hope this helps
PS Take a tool kit to deal with unknowns..... Better to have it and scare away any problems...
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
Google Custom Search For Sunline Owners Club