St Ives vs Penzance
 

I will be visiting Cornwall next May. I'm looking for advice on whether to stay in St. Ives or in Penzance, and if anyone has any good recommendations on places to stay. Two women in their 60s -- looking for an inn (vs. a B+B or large hotel) with charm, and the ability to walk to places in town for dinner.

I would choose St Ives every time. It has so much charm, lovely beaches and lots of small boutique shops. There are also lots of lovely restaurants and cafes. It gets very busy in the height of summer but in May (providing you miss the bank holiday and the school half term holiday which usually falls at the end of May/beginning of June) it should be fine.
I haven't been to Penzance recently but I would consider it much less of a holiday town. It doesn't have a lot of charm from what I remember.
I haven't stayed at any "inns" in St Ives so cannot comment but there are plenty of accommodation options. The one thing I would be aware of is that St Ives is very hilly so whilst so accommodations may seem very close to town it can make for a difficult walk (I am 25 and have regretted booking b&B's at the top of very steep hills!) I would check with the owner prior to booking if this is of concern to you

I'd agree that St Ives is far more "charming" than Penzance but it really depends on what you're looking for. St Ives has the Tate Gallery, Barbara Hepworth Sculpture Garden and lots (I mean lots) of small galleries. The Pedn-Olva Hotel is recommended. Porthminster Beach Cafe is excellent too.
Penzance does have the wonderful Penlee House Gallery, shops and restaurants and a range of accommodation. Also easy to take the bus to the lovely little Mousehole (pronounced something like "Mowzell")

We stayed in the Garrack Hotel in St. Ives and enjoyed it and our sea view. And we also enjoyed the food, which was quite good. However, the hotel is up a steepish hill. Wasn't any problem to us in our early 60's. But we live in a hilly city.

We used this as a base to do daytrips around Cornwall. We had a very hard time finding the hotel the first time, but there was an easy outlet to the main road without having to wend our way through the tiny streets of St. Ives.

Note: the OP probably already made this trip last May.

However, for others doing searches, we also stayed at the Garrack (back in 1998) and loved the panorama view. Spent a whole morning driving to and back from Lands End on the tiny back road. Loved seeing the stacks from the old tin mines which recalled to me the old Enid Blyton book "Island of Adventure".