I live in Myrtle Beach and have for over 11 years and know the area from Little River to Georgetown exceptionally well.
Murrells Inlet is three towns SOUTH of MB. Between MB and MI there is Surfside Beach, Garden City, and Soccastee. Murrells Inlet is just that, not a beach but an inlet. It is beautiful and just as everything along the Grand Strand, it is close to many attractions...although the main attraction of MI is it's seafood.
Somebody mentioned Nance's Restaurant. This used to be one that I would always suggest, but in recent years has gone down hill dramatically. Also, it is NOT included in the now very popular Marsh Walk.
The Marsh Walk (
http://www.murrellsinletmarshwalk.com/) is an area of a boardwalk along the Inlet with several restaurants, many with live music etc. It's a great place to kick back and relax. Great restaurants are Capt. Dave Dockside (GREAT and higher end), and Creek Ratz (laid back atmosphere and great food).....both are on the marsh walk with terrific views of the water.
And sorry, but Drunken Jacks is not somewhere I would suggest. Been there and would not take family or friends nor would we return. It's a bit over priced, ($38 for DD8 and myself) and two dining with us returned their entree's. This was as recent as this summer also, but to each their own - just throwing the word of caution out there.
There are also boat rentals (Dick's Marina is at Marsh Walk). Brookgreen Gardens is in MI and is an AMAZING place to visit (
www.Brookgreengardens.org) and Huntington Beach State Park is also close by (
http://www.huntingtonbeachsc.org/).
Into Garden City and Surfside, about 5 miles, you have water parks (Wild Water and Wheels), shopping, and mini golf, etc. Then you also have MB up the road about 30 minutes depending on traffic. South, there is Pawleys Island (BEAUTIFUL with cute shops) and also Litchfield Beach.
Hope that helps. Enjoy your trip! Any other questions about the area - I'm happy to help...not on the Dis that much lately so feel free to email or PM me.

Kelly
Kfentress@sc.rr.com