Mack is right on that unless your camper had a special order option for a walk on roof, most Sunlines are not considered direct walk on roofs. Since your year camper is a rubber roof, see these pics
The bud board looks like this
The roof truss system looks like this
To service items on the roof, use a cloth, carpet, tarp etc layed on the roof area you are going to work at to protect the rubber from abrasion. Then using 3/8 to 5/8" thick plywood, in sizes that are manageable to lift up and that will span 16" centers of the rafters. I use canvas tarp with 2' x 4' by 5/8" plywood sheets as that is what I have laying around. I over lap them as needed to get 8 feet long etc.
See this post at the end as I am servicing the AC unit.
Hope this helps and good luck
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