We spent almost two weeks at Hillsborough River State Park located east of Tampa about 15 minutes from I-75. It is very popular and fills up on the weekends. When we weren't visiting with our daughter's family we were enjoying the wildlife and walking along the river where we saw some huge cypress trees. It was usually foggy when Blondie and I went for our morning walks.
Hillsborough River is just far enough off the Interstate to be very quiet and remote, yet close enough to Tampa that it is not a bad drive.