You can crawl under rigs, you can go inside, open cabinets, sit on the toilet etc. The busier the show, the harder it will be to do though. I don't care... I wore older clothes and crawled underneath campers when I was getting serious and looked at all kinds of stuff. I brought a measuring tape and took detailed notes of clearances. I looked at how the underbelly was enclosed on different models. I compared how the steps felt as you climbed inside. I asked for permission to pull the slides in to see how they worked and how much room was available. I opened cabinets and measured inside space. I got inside shower stalls. I laid in beds.
You just have to be prepared for people giving you a weird look. Some people walk into these shows and drop $60 grand on a camper that they just opened the door and looked inside. I'm not that guy. I researched manufacturers for years, then spent an entire year researching models after I narrowed it down to a Jayco product. I would go to 3 shows a year (Hershey PA, Dulles VA and Timonium MD) for about 3 years before we bought our current trailer. I knew this thing better than the salesman did... and I only spent $21,000.
