I cannot speak toward the 950S model. I have an older Lance model 1030 with a built-in Onan propane generator. It does NOT come out through the door. The entire door frame needs to be removed (a few screws and cut the caulking). Then there is enough space to remove it.
IIRC, there are a few bolts holding it in on the bottom. Need to disconnect the propane line and remove the muffler. Disconnect the power lines too. In my case they are under the dinette floor. So take the table out, unscrew the floor, and disconnect the wiring.
One person can lift it if needed. Best to have something ready to set it on. I think it is around 125lb or so. Even better to have a friend help.
HTH!
-Eric