Keep your boat. If you take that one out of the Tweed bar then there's nothing to trouble it up here. Lots of close reef bommies and islands around Mackay. Fuel usage/range might be your only concern with the big 2 banger, there is a lot of inshore and offshore options. You can't go too far up the river, imagine tweed bar to the bridge is about all there is accessible all tides. Almost all creeks are very shallow and pretty short like Cudgen creek. More to find exploring the coast.