can I file a single flight plan

There is something called a "through clearance" that would allow you
to make a stop on a single IFR plan, but you can't file for such a
clearance. You have to ask your controller for it and make darned
sure he understands what you're asking for. I learned this the hard
way. ;-)

All IFR flights are suspended while you're on the ground, so he would
be unlikely to give you such a clearance if there's much IFR traffic
in the area.