If trailering is no problem, come on down to Orange Beach. You are only 45 mins away down Hwy 59 South to Hwy 180 East. The Gulf of Mexico welcomes you.
Mobile Bay is good for fishing the banks, but power boating is only good if you know the water. Be wary of shallow spots and trash (crab pods, duck blinds, alligators).
The Orange Beach / Gulf Shores area has plenty of inshore and all of the offshore boating you could possibly ever want.
There is 1 public launch in Gulf Shores under the Hwy 59 bridge (no charge), and 2 in Orange Beach: 1 just east of Hwy 161 on Hwy 180, and 1 off Marina Road approx 1/2 mile north on Hwy 161 off of Hwy 180 (again no charge).
Hope this helps, Enjoy.