kaboom
In that case I'll use 5 months like so:
Month 1: Create 100,000 pocket dimentions. Hide in one of them.
Month 2: Summon 100,000 PL of outsiders.
Month 3: Resurrect 100,000 PL of the dead.
Month 4: Create new race of beings: the living Spelljammer. It can regenerate 1000 points of damage per round, sustain the crew with eatable snap-off appendages, put people in suspended animation, and shoot bursts of spellfire at enemy ships.
Month 5: create a Giant Ooze that can morph into any form. These things can be commanded by any Illithid or any Chosen of Mystra, but the Chosen takes precedence. These things can not attack any living being, for it is TOTALY against there natures.
Month 6:Go home with the new army.
ANSWER:
You can do all of these things. Consider your first project begun.
However, you may change your mind at any time, drop the project, and accomplish something that takes less time to do (a week-long action, a day-long action, an hour-long action, etc.)
Furthermore, I would advise against creating pocket dimensions just so you can hide in them.
I have been very specific in stating that pocket dimensions are no protection against 11th level magical scrying.
They really are not the protection they are made out to be - not against 11th level magic.
Against 9th level magic and below, they are great.
Against 10th level magic, so so.
Against 11th level magic, very little protection.