Update: Over stove vent is closed, box access door is blocked, both vents have inserts, over cab windows have the reflex material taped in place (easily removed in case I need / want to), starting to put storm windows back in (doing a modification from past years, still working it out as I want to be able to take them out easier than removing the screws).
Results: In heating up the camper it is A LOT faster. It heated up from 3 C (37.4 F) to 16C (60.8) in 15 minutes. Feels a lot warmer and less drafts.
To do: Finish putting in storm windows and then test camping and when driving, possibly this weekend.