I would suggest that you get your hands on a copy of the
Texas Cruising Guide from Campbells. It runs the entire coast.
The trip to Port Aransas is generally a 24 hour trip
offshore - and then a leisurely trip back up the
ICW, or vice-versa. There are places every few hours to spend the night.
A few "don't miss" places:
Army Hole, Matagorda Island State Park
Mud Island, behind Matagorda Island, across from Rockport - just don't
anchor with a norther threatening.
If you have the time once you get in the Corpus Christi area, downtown CC is fun for a night or 2, with lots to do within walking distance or trolley distance.
Port A is fun, and eclectic. Look us up. You can generally walk or get a quick ride to
shopping and restaurants.
Ingleside Cove is probably the nicest, safest anchorage on the
Texas Coast. It's weird, because there's a rig
builder on one end of the cove.