Last year we replaced a 60 year old forced air furnace with an American Standard, 2 stage variable speed. 150 year old house, the downstairs seems to have adequate returns, but the upstairs does not (5 smaller sized rooms, with only 1 return which is in the room furthest from the center of the house). In the winter we have dry dry air, sniffles, bad throats, etc.... We need cleaner moister air and we are thinking of adding an air cleaner and humidifier before next winter (don't ask why we didn't with the new furnace).

1) Are there suggestions as to which air cleaner and humidifier to add for an old old duct system?
2) Will the lack of returns upstairs substantially limit the benefits of an air cleaner and humidifier? Unfortunately more returns cannot be added the basement as there are no closets, etc. to drop through.

(hope you all don't mind, I ran this question on the IAQ board, but didn't get a response)