Congrats on you new to you Sunline!
Here are some answers to your questions.
1. The Roof, if your roof is a rubber roof, see here on how to seal the caulking and how to prepare to walk on the roof. Most Sunline campers do not have direct walk on roofs and need precautions taken first to be able to walk on them. A heads up on silicone, while silicone is a good product, an RV roof is not a good use for it. It may work for a short time, but not a long time and once the surface has silicone on it, it is very hard to have anything else stick later.
2. The holding tanks, I do not know if your model has a tank monitor or not. The older ones did not but then they changed and most have a lighted tank monitor system. I just do not know what year they changed.
However, by using a flash light and holding the foot pedal toilet valve open with the water off, you can see how full it is. The gray tank will back up in the shower drain if it becomes totally full. Assuming yours has a shower.
3. The awning, Is your awning one that rolls out and retracts with arms on the side and a roller for the awning or is the a bag awning like used on a Pop Up? (set up with poles and manually roll it up?)
Covers for the rollup type have been made from 4" PVC pipe, plastic U shaped gutters or vinyl covers.
Here are 2 posts on home made covers.
Hope this helps and happy camping
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
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