(3.P) If I needed to boost someone's Stealth for a day, what are the best spells?

[RPGaddict28]

My party has to sneak into a tower to destroy it. Thanks to an Inquisitor of ours, we only need 1 person to be stealthy. I have 9th level spells at my disposal. The enemies likely have True Sight but we don't know that. Any spells for 3.5 or Pathfinder can help.

[Malroth]

Shapechange to a Diminutive or fine creature for size bonuses, Silence to prevent detection via sound, Non-detection and mind blank to ward of divination Guidance of the Avatar for raw skill bonuses, Meld into stone to avoid rooms where detectors are.

[peacenlove]

http://www.d20pfsrd.com/magic/all-spells/p/paragon-surge

Paragon Surge -> Darkstalker


Silence to prevent detection via sound
http://www.d20srd.org/srd/spells/zoneOfSilence.htm
IMO it is better for being silent. Other than that incorporeality via ghost form or other source greatly helps for not triggering traps.

[ericgrau]

Extended invisibility spamming, and silence/zone-of-silence via limited wish. For the actual skill checks items are nice. You can wish for them or purchase 8x each of the hide and move silently elixers. Or however many hours you need. 1 of each might be plenty to give a +10 to each skill for 500 gp.

[Jack_Simth]

Polymorph Any Object and Mind Blank. You want the Pathfinder version of both. The Pathfinder version of Mind Blank explicitly stops True Seeing, the Pathfinder version of PaO does not change the subject's intelligence score. Turn him into something as small and inconspicuous as will work for the situation, use Moment of Prescience on the Disguise check (Disguise is opposed, so MoP works for this... and you only make the one check, so that lasts you the entire duration of Polymorph Any Object). Oh yes, and most equipment remains functional with the Pathfinder version of PaO - can't activate stuff, but other than armor, shields, and weapons... anything that gives constant bonuses continues to work while melded.