Wow! You've used up your quota of Scamping misfortunes!
Do check frame and axle
condition/alignment from the roll-over. Inspect the coupler very closely.
Most parts are available from Scamp. Not all are shown on the website, but it's better to order by phone anyway for a cheaper bundled shipping rate.
Before you call Scamp, many bits and pieces may be available even cheaper from Amazon or other online sources. Beyond the shell, frame and upholstery, Scamp buys parts from common RV suppliers. Sometimes the trick is knowing exactly what a part is called to do the search. This forum is a great help with that sort of thing.
hatch is an unusual size, so you might have to get it from Scamp. But since you're doing fiberglass work anyway, you could fill in the escape
hatch opening down to the standard 14x14 and install a powered roof vent (Fantastic Fan or Maxxair). Something to consider if you have the rear slider, which provides alternate emergency egress.
Best wishes getting her all fixed up!