Just returned from 2 weeks in the Orangery - a lovely property just 5 minutes walk up St John's Hill to the North Beach and top of the town. Another 5 minutes will get you to the South beach. Property was spotless and included everything you'd need for a stay. 2 toilets in upstairs bath/shower rooms and 1 downstairs in utility with washing machine and dryer. Beds comfortable, big lounge with gas fire and freeview tv/dvd.
We travelled with 3 teenage boys and this was great accommodation for us. There are steps up to the property and Tenby itself it pretty hilly so it may not suit someone with mobility problems. The owner was very helpful -quickly replaced the dryer the following day when it broke and lent us a map when we told him we were going to St Davids.
Tenby was a great base to see Pembrokeshire. We had mixed weather so only got on the beach a couple of days.
Would recommend the Tudor Merchant's House and Lifeboat station in the town. Also St Mary's church is worth a look at. Qube does a lovely meal, although pricey for a family ( they do an early evening menu cheaper, but no-one ordered from it!!) The Buccaneer did a good meal too and has a lovely beer garden. Get fish and chips from the shop in Lower Frog Street - the others aren't nearly as good. We went on the Ghost Walk, which was just average I'd say - very pleasant and entertaining guide, just the stories weren't much cop. There's a Tesco Express in the Main Street and a bigger Sainsbury's handy. At the bottom of St John's Hill just a minute away is a Spar at the filling station which is good for milk bread etc.
What else? A trip to Heatherton was great and the Treetops well worth doing. Oakwood theme park great day out as was Caldey Island. We took a wildlife trip from Cardigan and this was very enjoyable although we only saw 3 dolphins briefly and a few seals. Plenty of birds though and the inflatable boat was an experience in itself. Chocolate factory was good, but maybe better form younger kids, Blue Lagoon water park was good for all the family - would be excellent for younger ones and you could eat there without getting out of swimwear which I hadn't come across before.
Hubby and I went to Laugharne to see Dylan Thomas Boathouse. Worth a trip but don't eat in the cafe as it seems very overpriced.
Manorbier Castle definitely worth a visit and the beach is lovely too. You can have a picnic there and get a cup of tea at the tearoom. Pembroke castle terrific. Walked round Carew castle and mill but didn't go in ( castled out by then!). Seemed nice and the walk round the lake was pleasant.
Tenby is a great base to see lots of places and even if the weather isn't great, just get out and go for it - it rarely rains all day without ceasing. The Orangery is a great, quiet and pretty convenient place to stay. You'll have good calf muscles by the end with all the hills!