South side of Maui is long and sprawled out - miles and miles long, but only one 'block' wide. Spots tend to be pretty small and basic, separated by construction sites, condos, residential, or natural areas full of kiawe trees [big sharp thorns].
Shops at Wailea - about the only thing in Wailea that isn't hotel property. It's upscale, so I would expect security to be a hassle, but the little I've done there hasn't been a problem. A lot of possibility, including big drops.
Wailea resorts - great if you're staying there. Otherwise, trespassing laws are stronger on hotel property than non-hotel property. If you are a guest, you can get away with quite a bit, as long as you make it look like part of a corporate scavenger hunt or something similar.
Kihei:
Azeka Makai - this mall has the best features for PK - outdoor, multi-floor, funky construction with rails, stairs and planters in front. The back side is bordered by private condos/ apartments and Star Market - the fences to Star are low, but parts are in bad shape. During the day people may be working back there - especially at the scuba place and the Vietnamese restaurant. Security is more active here than at any other mall I've been in. I've been warned away once. Don't bother going by the post office - busy and the concrete is crumbling/ in bad condition.
Azeka Mauka - Trash corrals by Stella Blues, some stuff by the Coffee Shop. Not much else. Back side borders Lipoa Center, and is in bad shape - loose concrete blocks, homeless.
Long's Plaza - Both front and back are pretty boring. Loading dock area has some possibilities.
Star Market - Lots of railing at the front. Fairly low fence to Azeka Makai. Parts are in bad shape. "Homeless nests" in the back.
Paradise Plaza - Atrium may have some possibilities. Low wall between plaza and Jack In The Box, also between plaza and Lipoa Center, but watch out for "homeless nests".
Lipoa Center - If awnings support weight plus force, this would be a great place to test out laches. Trash corral mauka side on Lipoa St is nice, but kinda high traffic.
Kihei Elementary & Lokelani Intermediate schools - Kapu. Looks like some possibilities, if you're under 13.
Haggai Institute - Kapu. Private property with security and video surveillance.
Pi'ikea Plaza - front side - some stairs, walls, a few rails. Security likes to hang out by Safeway [tan uniforms]. Private security in Safeway [blue jackets]. Back side has more obstacles, including chain link fence to soccer field/ residential area.
Kihei Community Center - Multiple levels, stairs, rails, ramps, walls, trees, tae kwon do, and swimming pools. I'm going to start doing a lot of runs and training here. Nice open gateway in back to apartment complex across from Pi'ikea.