Even if the wife did risk falling to look around for squeeks...how can she tell what is making them ...you would be asking her to be able to diagnose all those sounds correctly?!
But if you share our issue with her maybe she'll be more attentive...because, yes, serious issues can be heard ahead of time that can cause a serious accident or damage the rig: On our maiden year voyage we were rolling down at highway speed approaching our turn off to head down to Scotties Castle in CA, heard a sound near the rear of the coach that sounded like metal clanking. I did get up to investigate, could not locate what it was so we pulled over and the sound stopped. However in our haste we did not crawl under the coach. We turned and headed on down the hill...when suddenly the warning buzzer for the air system went off...we rode down the hill on the engine retarder without touching the brakes, pulled into the parking lot at Scotties Castle just as the air brake system dumped completely therefore the air brakes locked tight. We stayed overnight, called Frieghtliner and Tiffin from the ranger's office, then waited for the lowboy to come haul us on into Las Vegas. The air dryer had fallen off, rubbed on the drive shaft making a hole which of course let the air out...The tow driver told us if the air had gone out quicker & at highway speed the brakes would have locked and we'd most likely would have rolled/wrecked...he said we were lucky to be alive! So as newbies we learned a very good lesson--do listen because your life may indeed be on the line! We found it was indeed Tiffin's problem...when they attached the rear jacks the air dryer wasn't bolted on with enough bolts...that one bolt broke. The found at least one more rig on the manufacture line with the same issue...Tiffin of course paid for everything and from then on they stepped up their quality control for this issue.
I'd suggest if you are really worried about serious issues...find someone to take a long ride with you that can tell what to listen for, locate an issue that may be serious or ease your worries!
I too would kindly suggest she learn to drive, not just so you can sneak around listening to squeeks. The most important point is...what if the driver has a medical emergency behind the wheel? Will she be able get into the chair to get the rig to safety before it goes off the road and kills everyone? And what about driver fatigue...a driver falling asleep at the wheel is just as serious. Hey gals...you can indeed drive. I am the female part of our traveling team and I drive about 50% of the time and know as much about the systems on the rig has he does. We gals have to be able to handle it because...if you find yourself in a fix...hey gals you can indeed take care of yourself and your spouse!