Obviously, a hire car is easier, but Jersey has an excellent bus network. Have a look at
https://www.libertybus.je/ for details, and to get an idea of frequencies for the various spots you're planning on visiting. They also have a (very cheap) folding bike hire scheme if you want to go little further off their routes.
This handy map shows the main hotels on the island, and the bus routes they find themselves on. Predictably enough, the network is centred on St Helier, but St Aubin and St Brelade (IMO the nicer places to stay in) aren't badly served.