Hi Kham,
Lake Mattress in Mooresville is no longer open but you can visit the Lake Mattress factory in Conover and they can put layers together that use the same materials as the Rocky Mountain mattress you are looking at to give you a good sense of how their mattress will feel.
Night Therapy is one of the Zinus brands and you can read a little more about them in post #31 and #32 here along with post #2 here. A forum search on “Night Therapy” will also bring up more information about them as well including this post which would be a typical experience with lower density or less durable materials. I would tend to avoid most of their mattresses because they use lower quality/density materials than I would be comfortable with (see the guidelines here).
The better options and possibilities I’m aware of in the Winston/Salem / High Point / Greensboro areas are listed in post #2 here.
Dreamfoam only sells online so everyone that has purchased them would be buying them sight unseen. A forum search on Dreamfoam or on Ultimate Dreams will each bring up hundreds/thousands of posts that mention them which includes a great deal of feedback about their mattresses from the members here. The Eurotop provides the option of changing the firmness of the latex comfort layer which can help reduce the risk of choosing a mattress that is too soft or firm that you can’t test in person. A forum search on Ultimate Dreams Eurotop will bring up more specific information and feedback about the Eurotop as well. I would be cautious though about using other people’s experiences as a guideline for your own because a mattress that is “perfect” for one person in terms of PPP may be completely unsuitable for someone else to sleep on and if you are considering an online purchase then I would always make sure that you have a more detailed conversation on the phone with an online manufacturer or retailer so they can “talk you through” the firmness level that has the highest chance of success and then you can use the firmness exchange option as your “backup”.
The mattress shopping tutorial has all the most important information, steps, and guidelines that you will need to make the best possible choices but of course if you have any specific questions that aren’t answered there then I’d be happy to answer them to the best of my ability as well.
Phoenix