If you've got your mind made up to do all of these then:

-Use your time till the MTB race to build and start some intensity a 2-3 weeks before the race.
-Use the MTB race as training and make sure you don't dig yourself into a super huge hole before the road race.
-Use the time after the MTB race to take a day or two off or ride easy, and then start doing some longer rides with bits of intensity (Threshold/Vo2/anaerobic).
-Use the last week and a half before your stage race to cut all volume in half but keep up with the intensity. Do a recovery ride for the 2 days leading up to the event and then have at it.

You won't be able to pull this off unless you have a pretty huge base. It's August right now, so you can still give yourself a good shot at finishing all of these, but you're going to have to be really disciplined.

I have no idea about TT's so I'll let the others speak for that.

PS: You're probably looking at burying yourself for a bit.