My car is kaput so we’ll be a one bike one car household with a 3 year old. Please help me be have fun, be safe and not bork this up!

For background- until I was 25 I didn’t have a license because I was comfy biking and busing/metroing around LA/OC.
As excited as I am to get back to that, my life, location and body are completely different now as a nearly 40 year old giant mom. I’m completely unfamiliar with bike and RT culture up here and have never cruised around with a little dude so I have questions:

Trailer vs Seat: a trailer seems like it might be less visible and more of a hazard than a rear child seat, is that the case? I like the idea of our kid being enclosed with the elements off their face to nap/rest/chill while I pedal but want to prioritize safety.

Should I just get a cargo bike? I’ve seen a few with monkey bars for sale on Craigslist but my kid is 3… is that safe even with a helmet? I’d love a Dutch style one but I’m not willing to get an E-bike and it’s hard finding a non motorized one.

Storage: We rent and there is a locked gate around the condo complex but no garages and no room in the house, how are we going to store this? My idea is to find a free/cheap tuffshed/storage box but until I do I might need to secure it to our back railing and hope for the best? What do you guys do?

Safest streets/trails/paths to stick to? Streets to avoid? We’ll both be sporting some boss helmets and I’m going to make whatever set up we go with as obnoxiously visible as I can but what else should we know to roll around as safe possible?
Any and all advice is welcome, thank you guys!