My Alpenlite (1994) used silicon on the window and compartment seal edges. When it got old, I removed the excess with a razor blade and reapplied silicon sparingly. On the roof, I would use Endurabond. Sticks to all surfaces except silicon. Never use silicon on the roof. There is an Alpenlite travel club on face book with owners of older Alpys like yours.
2001 dodge 2500 auto, with billet Mojave Green torque converter with 2nd gear lockup mod, raptor 100 fuel transfer pump and gauges. RV75 injectors
94 Alpenlite 27sl with many mods.