What is the best portable air conditioner/fan/etc option for me? Need to move from room to room on a daily basis. Upstairs/downstairs.?

I'm with most of the posters here with one exception, don't buy a new window unit, buy them on on Craigslist or OfferUp etc. You can test before you buy and for 100-150 bucks you have one for each room, are recycling to a degree, and saving money. Unless the windows in your two rooms are identical, moving a portable unit will be a pain and they are less efficient power-wise. 

The window AC units are undersized or they can be just dirty.  Pull them out and, remove the panels and clean the filter, coils, condenser fan and evaporator blower with a pressure washer.  No luck, replace the units with a higher cooling capacity. It is a better option.  Do you really want to lug that portable AC everyday?  I don't think so.

Get another window unit.  In fact, get a couple.

Why: for what a typical portable AC costs, you can just about buy two window units.  If you're already considering the portable then you can probably make the budget handle a couple of window units.

Are they too heavy to carry up and down: YES.  

Caveat: not really, not if you're in any kind of shape and the stairs aren't too steep or narrow.  But the portables aren't light or small and that kind of toting gets pretty tiresome pretty fast, even if you only do it once a day.

Seriously.  Spring for a couple of window units instead.  It's a better solution.  

You aren't going to want to carry a portable up and down stairs all the time.  They aren't cheap either. You could buy 2 regular window air conditioners for about the same price. Make sure to get the right BTU size for the size of the room.

Portable will work, but be sitting down when you get your electric bill.