@alewojtowicz Thanks for reaching out!
Renting is a great way to try out some gear before committing to a purchase! A tent like the REI Co-op Half Dome 4 could be a really good option, but at over 7 lbs you're pushing the limits of the weight for a backpacking tent. Depending on the size of your dog and how cozy they like to sleep, you might be able to drop down to a two person model. It is a little bit longer so there is some extra room over a 'normal' 2 person tent. If you put your pack and boots in the vestibule, you may be able to comfortably get everyone inside. I've spent a lot of time in the backcountry with my dog and while the 'dog sleeping in the vestibule' idea sounds good, my dog has always wanted to be in the tent with us.
We encourage you to check out our Outdoor Gear Rentals page to see which stores are currently renting gear. Additionally, we recommend reaching out to your local store to see what rentals are available.
Hopefully this helps, have a great camping trip this weekend!