Hello, Mike - welcome to our band of "Happy Campers"!
If you have a 33' model, it is just about the biggest one HiLo ever made. To learn about its features, including how to raise and lower it, go through these videos:
Start with video #1 and just proceed through at your own pace.
HiLos did not change a great deal through the years, so I believe you'll find the topics in these videos will apply to your trailer (almost verbatim).
You will definitely need a Weight Distributing Hitch and I'd get one with sway control too. To pull it, you should probably have a 3/4 ton truck (mostly due to the weight the hitch puts on the tow vehicle's suspension).
Trailer tires are normally unsafe long before their tread wears out, so don't let the tread be your guide. I believe the standard advice is not to use the tires longer than 5 years. The heat generated by flexing breaks down their inner structure, which can lead to a blowout - something you never want on a trip.
There are some owner's manuals in the library on this forum, and you can probably find one that is close to the one for your model. And, you can find manuals for the appliances in the trailer here too:
Reference Library - Hi-Lo camper travel trailer forum
You'll have more questions, so just ask when you do.
- Jack
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