Hi Laura E,
Welcome to the Mattress Forum! 
I would start by reading the mattress shopping tutorial here. Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort”, firmness, and PPP that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on all the parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
When reading the tutorial, don’t attempt to memorize everything. It’s all here for you to come back to as many times as you like. Read it more as you would a good book, going through the information and exploring some of the different links should they be of particular interest to you. Use the tutorial as your reference and you can make notes of things to ask when you visit any retailer. While the guide is certainly detailed, there are two “shortened” versions of it towards the end of the guide.
While nobody can speak to how any specific mattress will “feel” for someone else or whether it will be a good “match” in terms of comfort, firmness, and PPP because this is too subjective and relative to different body types, sleeping positions, and individual preferences, sensitivities, and circumstances and you are the only one that can feel what you feel on a mattress … outside of PPP (which is the most important part of “value”), the next most important part of the value of a mattress purchase is durability which is all about how long you will sleep well on a mattress. This is the part of your research that you can’t see or “feel” and assessing the durability and useful life of a mattress depends on knowing the specifics of its construction and the type and quality of the materials inside it regardless of the name of the manufacturer on the label or how a mattress feels in a showroom or when it is relatively new so I would always make sure that you find out information listed here so you can compare the quality of the materials and components to the durability guidelines here to make sure there are no lower quality materials or weak links in a mattress that would be a cause for concern relative to the durability and useful life of a mattress before making any purchase.
There is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range.
Aside from all of that, subject to confirming that any retailer or manufacturer on the list you plan to visit is completely transparent (see this article ) and to making sure that any mattress you are considering meets your specific criteria and the quality/value guidelines here … the better options or possibilities I’m aware of in and around the Minneapolis/St Paul area are listed in post #2 here .
This should give you a good start in your mattress shopping process. Please take a bit of time to read through things, and feel free to post back with any specific questions you might encounter along the way.
Good luck!
Phoenix