I'd use what I used last weekend in Devon
Neoair and a Montbell Downhugger 7, its a +10C bag so perfect for indoors but more importantly its stretchy and light, and easily openable to form a blanket.
Takes up little space so easy to move around. If you're setting up a permanent interim solution, then perhaps something like an Aerobed PakMat? Often go on sale with a pretty hefty discount on places like amazon