Dicor self-leveling lap joint compound is a standard product for roof sealing, as was mentioned. Don't try to use it on vertical surfaces; it'll self-level down as a drip.
For walls, some sort of a urethane caulking is good. Geocel pro-flex RV is probably the "standard" but there are other very similar products available that work pretty well too. I've used (with good success) OSI Quad, for instance. Avoid silicone; while it seals effectively, once cured essentially nothing (including more silicone) will ever stick to it and so when it needs renewal it's a major hassle to first remove every last speck of what was there.
For cleaning the roof, I use a string mop and spic and span (and water). Laundry detergent also works pretty well. It's not like the roof needs to be absolutely immaculately spotless, at least by my thinking.
If you don't have a #2 Robertson (square drive) screwdriver you can keep in the trailer, get one ASAP.