As-salamu alaykum - What mosque etiquette should I know before visiting a Masjid?

As-salamu alaykum! I'm planning to visit a local masjid in my city soon. The mosque page doesn't say which school it follows, but my area has lots of Syrians, Somalis, Turks and Kurds, if that helps paint a picture. A few things about me: I'm a devout pagan/heathen (not looking to convert, happy to answer questions about that), and I dress a bit… eccentric. I'm a man, and I usually wear a long skirt because I overheat really fast. I know men are generally expected to cover their knees (especially during prayer), and I'm worried my skirt might ride up if I move around on the floor or crouch. I want to be respectful - any tips on that? Also, since I'm not Muslim, I don't intend to participate in worship as someone with intention to pray to Allah. Should I sit toward the back and quietly observe, or is it okay to sit more in the middle or closer in while just watching? I plan to arrive early to speak to the imam or mosque staff about the rules before anything starts, but I had a weird experience at a Hindu temple where the priest didn't speak English and it was hard to get guidance, so I'm trying to be prepared. I have two reasons for going: one, I want to learn more about how Muslims worship so I can better understand some friends from different traditions; two, I'm curious to see if there are practices I might respectfully learn from and adapt into my own spiritual routine. Jazakum Allah khair for any advice - I'll try to check back before and after my visit, insha'Allah (probably in about three weeks).