Not a big Venice fisherman, but the only other Marina I know of down there is Cypress Cove. It's used to be a little nicer than Venice Marina, but since Katrina I couldn't tell you. Link:
http://www.rodnreel.com/cypresscove/html/marina.html Venice and Cypress Cove are less than .25 miles from each other by boat.
The jump (the east-west passage from Vencie and Cypress Cove Marinas to the Miss. River) is navigable by MUCH larger boats than what you've got there so no worries on that account. Two basic ways to get to the Gulf from either marina. The river passes or Tiger pass. and all should be fine for that boat but check on Tiger pass before you travel it and see if bouys, markers are up since Gustov-Ike. Southwest pass is the largest and SW and South pass are both very easy to navigate. Never been thru East pass, but I hear it can get shallow sometimes.
Probably at least a 2 hour ride from the NO airport to Venice.
If you can't get a slip in Venice, Grand Isle is good too. Especially if you're going to be fishing the West Delta area. If fishing east of the Miss river delta, then Venice is definitely your best bet. Link:
http://www.grand-isle.com/
good luck