Go checkout ductwork in the store.

The microwave does vent to the exterior, so moving the cabinet may require running ductwork over to the current cutout in the wall?

I'd like to hear some guesses or first-hand accounts of how much it costs to install HVAC and ductwork in a house that currently only has radiator heat.  

There is plenty of room in the basement and attic to make running ductwork possible.

@Brian Kloft I have the heaters you mentioned as well as heat pumps with duct work.

Heat probably gets to third floor just fine, if sufficient ductwork exists.

I think when rehabbing, some folks pull out old boilers and radiators and want to avoid the upfront cost of ductwork and forced air - so they put in electric baseboards.

Here is what I would do: block off the duct work to the "extra" bedrooms.

And it may end up being cheaper (relatively) to just remove the top of the roof and put in new trusses, joists, insulation, duct work and reroof.

The bathroom floor and part of the subfloor in the hall and kitchen would have to come-up; the wall between the bathroom and hallway and across the end of the hall would be going back to the studs; the common wall between this apartment and the adjacent unit would need to be brought up to current {fire} code; the ductwork for the HRV needed to be replaced; and three of the existing windows had broken thermo panes.We also planned to improve the energy efficiency of much of the envelope during this renovation - the amount would depend upon what we found behind the drywall.What we found:The damage to the subfloor on both levels was more extensive than forecasted and I wasted two weeks, and a few hundred dollars in materials, over the holidays in December trying to remove the smell of pet urine (ozone, enzymes, sealant, etc).