Protections for a high level wizard?

[Jack Simth]

If it's a warrior, sure, just pack your sword and your armor and you're done. But a wizard needs a lot of stuff. Books (lots of books), lab equipment, spell components, magic circles, possibly demonic pets - a whole crapload. Not all of it is portable. It would be a pain to move it every day. And permanent shrink item costs xp. lots of xp, because he'll be doing it a LOT.

No lo contendre. Of course, this isn't for a PC, but an NPC, and:

Assume that he's had a lot of time to prepare, and he has the resources to make pretty much any items available to him at his class and level.

I was just following instructions.

If he summons up his demons in portable holes, and he can't get thier agreement that day, he can just close up the portable hole and try again the next day. Or let them suffocate. Either way. This wizard, as described, isn't a particularly good chap, but even if he is, killing demons is [Good], right?

He could have several pack-mule golems made, and have things sorted by type ("BookCaseGolem - get over here ... let's see ... here's the book I wanted ... ah, I need the lab ... LabGolem - get over here ... and a few ingredients ... ") perhaps having each carry some Handy Haversacks for quick pulling of a specific item. Perhaps he might have a familiar that can do some of the grunt-work of ordering the golems about and supervising them over finer, but mundane, details of setting up the lab while the Wizard himself researches the action in question.

Granted, some of these depend on DM adjucation on things like Portable Hole/Mages Magnificient Mansion/Secret Chest interactions (which isn't directly addressed in the rules - there's a note that it's "dangerous" to do such things under the description of the Rope Trick spell, and there's the specific results for Portable Holes/Bag of Holding, but specific results for other cases aren't addressed). If you can't safely bring/use a Portable Hole into a Magnificient Mansion, then he is going to need some semi-permanent headquarters. With a month or two of work with Wall of Stone and Shape Stone, he can have a quite nifty abode, that he can put up just about anywhere (perhaps some water spells and a Transmute Mud to Rock for the base that Wall of Stone requires).