[ShrimpBurrito]

I've heard of people using the powered movers to guide their TMs into a garage up a slope, so the safety of that and appropriateness of your exact setup might be worth investigating a bit. Post a picture of your garage and driveway, and maybe we can come up with some other ideas.

IMHO, if you have a leak at one of the roof vents, you need to pull it off the roof completely, build new risers (or buy them from the factory), and reinstall and the risers will just keep cracking and you will keep getting leaks. Note that the ones the factory uses are "plastic lumber", and they staple them together at the corners with huge staples, preventing them from laying flat on the roof. A better option, which is what I did, is to by some PVC boards from Home Depot / Lowes or a similar place and cut your own (or have someone else do it). That way, you can glue them together with PVC cement, and also put a stainless screw on the corners to secure the lap joints.

Once the roof is completely cleaned of all the old sealant / tape, apply some butyl tape on the riser and press it on the roof. Then apply more tape to the top side of the riser, and place the vent on the riser. Reinstall the clamps and/or screws that were there initially to secure it to the roof, and then apply DAP self-leveling lap sealant to cover the vent flange. I then used RV Proflex sealant to seal the gap between the riser and roof. You could probably use 3M 4200 there too.

Dave