I wouldn't use would in those, but either the present subjunctive or the past (subjunctive) seems appropriate.
I'd rather --
he join me / he joined me / he not join me / he didn't join me
the appointment [be / were] rescheduled / [not be / were not] rescheduled
the meeting [take / took] place tomorrow / [not take / didn't take] place
the meeting [be / were] canceled / [not be / were not] canceled
it [happen / happened] now than later / [not happen / didn't happen] now
My personal choice is probably more often the present subjunctive, though I can imagine myself using either one.
CJ http://www.englishforums.com/English/SubjunctiveAfterWouldRather/gbgdn/post.htm