As others have said pushing around a 12ish foot aluminum "Lund style" boat is no big deal at all. Even if it does not have a swing jack (wheel that drops down that you can raise or lower) it should be no problem to pick up the tongue and move it around. When I lived in a town house I had a 12 foot aluminum on a trailer. It was too tricky to back it into the garage so I would just unhitch it and push into the garage and rest the tongue on a milk crate.
I am not an expert here but I've owned a few tin boats and trailers so here it goes:
-decent used 12ish foot boat on a trailer should run you 1000-1500 this time of year. A bit more or less if it is really new or really old.
-if you know nothing about boats and trailers it would be best to bring someone who does before you hand over cash.
-plug the trailer in and make sure the lights work. Fixable if they don't, but you should get $ off if the wiring/lights are screwy.
-have someone check over the wheel bearings. if they are noisy/loose that is a safety issues and more $ you will have to spend to make it road worthy. you do NOT want to be that person on the side of the road with a trailer with a blown wheel bearing.
-if it comes with a motor great, just make sure it runs well if it is gas powered. if electric that is fine just make sure the battery is good. Anything more than 5 years old it's probably no good. New deep cycle trolling battery about $200.
I would avoid anything super old. Boat or trailer. Unless your budget is low in the $1000 range. I would save your $ and buy something newer, especially the trailer. Older boat is fine if it not beat up.
Good to buy off someone you know who you know looks after their stuff, or at least bring someone knowledgeable when you go to look at one you might buy.
There is a Lowe 1236 boat, trailer and motor on facebook marketplace Abbotsford asking $2500. Looks pretty good!
Flat bottom will be more stable laterally. Better for standing up in and moving around. Good for small lakes with minimal waves. However they such when the waves pick up. A Lund style v-hull will cut waves much better but a bit more tippy laterally if you want to stand up or move around the boat.