snow event

If it were me, I would bring the slides in before the snow starts and deal with it. The good thing about where you are is in a few days, it will be gone. The other thing is, once it stops, you will be able to put your slides out without any worries. The thing I would worry about is ice when the snow melts and then refreezes at night. It is a lot less trouble and cheaper to pull them in than deal with ice on a slide topper.

We have seen partially inflated beach balls that tighten the slide toppers in snow events!

A smaller space is easier to heat.
be sure you have plenty Propane.

It is your choice. When we lived in our rig in winter in snow country we pulled in our main room slide but left the bedroom one out (we have 2 slides not 3 or 4). Unless your slide toppers are old and brittle the snow will just weigh them down and the spring will tighten them back up when the snow is swept off. The main benefit is less space to heat, help reduce draft around the slide (mainly at the floor), and may help keep the pipes from freezing in your kitchen sink if it's on a slide.

You can try it with the slide out but I'd pull in the slide before it snows not after. If the snow event will be short it's not that inconvenient to live with the main slide pulled in. If you have a 4 slide out rig...it will get a bit cramped so again...it's your choice.