Hi macymom,
Subject to first confirming that any retailer or manufacturer on the list that you wish to visit is completely transparent (see this article) and to making sure that any mattress you are considering meets your criteria and the quality/value guidelines here … the better options or possibilities I’m aware of in and around the Philadelphia/Wilmington/Trenton areas are listed in post #4 here.
They should give you a chance to test some latex mattresses so you have some reference points regardless of whether you end up purchasing locally or online.
Phoenix