It depends how long you have and where you’re coming from. They cover quite a big area and island hopping is not as straightforward as you might think. You could easily spend a long weekend in either Jersey or Guernsey, particularly if you like history, beaches and seafood. Jersey’s transport links are significantly better than Guernsey’s, with direct BA and Easyjet flights to a number of UK airports. It’s a ten minute flight between the two islands (operated by Blue Islands) but there are currently only a few flights a day and they are not cheap. Both islands have a reasonable range of hotels and guesthouses - arguably a bit more of a range in Jersey than in Guernsey (ditto restaurants). PM me if you want any more advice. Sark and Alderney have unique charms but are more challenging to get to.