The parking lot for the Zoo & Zoombezi Bay is huge - you'll have no problems parking there. Stay towards the lot edges. However you won't be able to overnight.
Alum Creek SP will be pretty tight for a motorhome as it's an older CG originally built for shorter RV's. Less than 1/4 mile from ACSP is Cross Creek Resort
or you could also stay at Delaware SP
(both large rig friendly).