I've lived/travelled/sailed in Baja MX and northern coastal waters for decades, starting when my family would cross the border for dentistry and to visit family back in the 60s.
Regarding: leaving the car/quad on side of road- this is more possible due to mechanical breakdown/accident than legal problems, tho if you have an accident without good insurance it could get into a legal dispute.
Make sure you have everything in good working order, and check your auto insurance plan to make sure it includes a tow option to get your equipment back home. Also make sure you have the required amount for liability to cover accidental damage/injury. The amounts have changed, so consult with Discover Baja or another experienced insurance provider.
I've been in this breakdown situation, and we relied on friends in Baja to get our car to town when the transmission failed. Next time I'll pay for towing to US. Once we get to border, my AutoClub will take over. (I pay for extended towing with them, in case my truck with camper shell fails far from home/repair services)
The paperwork to bring in a boat legally can be ridiculous- they are less efficient than US, and we know how inefficient it can be here. I sold my interest in a 34' sailboat to a friend who lives/works and has residency in MX. I'll check with him when I visit later this winter, since he's in Ensenada harbor which has likely been hit by this latest "purge".
That said: Baja is a beautiful place to travel, explore and meet the people who live/work/play here. Don't let a few bad reports get in the way of discovering the natural beauty and friendly people who live in and love the peninsula. The benefits far outweigh the risks.
FWIW, The locals get frustrated with government too, because of delays in paving roads (pace has improved in recent years), battles over property rights (property ownership is still very complicated in MX). lack of electricity in remote areas (also improving in last 10 years) and the lack of understanding politicians in Mexico City, 2000 miles away, have regarding Baja in general.
However, this has changed in recent years. I lived in Baja in the 90s, just as NAFTA was passed. Lots of changes and improvements over the last 20+ years.
To prepare for a safe, drama-free trip: Get your FMM (travel visa), exchange your dollars for pesos (CostCo in Chula Vista will do this, if you're a member) don't carry drugs/guns (the checkpoints will inspect your vehicle, sometimes w/dogs, and don't act differently than you do at home (I've seen too many drunk/obnxious tourists make a bad impression). Do all this and you are much more likely to create an unforgettable trip for all the good memories you'll be making.
The attached image is of my favorite winter spot: San Ignacio lagoon, petting a baby whale.
Travel safe, smart and have fun!
