Well here in NY, I got my garage by word of mouth. A buddy had it already and rented space to his buddies. I came in as one of the renters splitting the rent (we rent 2 one car garage spaces). He found the space while trolling for transvestite hookers on, where else, craigslist (actually I made up the tranny hooker part, but honestly where else can you find them so easily these days?).

When I lived in new orleans, My first apartment had a parking lot, and I would basically bribe the building manager with kindness and trinkets so she would look the other way when I worked on stuff. I kept it neat and under a cover and nobody had an issue. My second apartment I looked for one with a garage space and got lucky and found one with an attached garage. It was awesome. Unfortunatly my roommate got married and I had to move out. So for the next couple of years I rented a storage space and told them I was storing motorcycle parts. As long as there was no gasoline in the unit and I spilled no oil they could care less. So I would take the fuel tanks off my bikes and empty them. Eventually I was able to rent space in a shop that was down there which gave me round the day access, tools access, you name it.

These are all viable options. If I were you I would check to see what the local storage places are charging and use that as your base line. If it is cheaper, make sure it has the same amenities. If more expensive look around and see if you are getting more, like tool access and such. Most shops if they have the space will allow storage of a bike, but working on it may be limited to their hours. Storage units are usually 24 hour access but they can be real intrusive. I told mine that I bought old wrecks and parted them out which is why they didn't have to worry about gasoline. I didn't at the time but eventually I did while I had that unit (and doing 2 bikes a year the unit paid for itself). By telling them that, and that I drain the oil and gas they didn't ask me any questions when I would work on the bikes in the unit, they just thought I was breaking stuff down.

you are probably not close to getting kicked out....yet...but once the problem ball starts rolling it is hard to stop. I think your landlord is worried that his place will turn into a junkyard and he doesn't want that. neighbors will complain, and he doesn't want that either. I find if you are uber neat and tidy about stuff, and the stuff you are working on looks clean, sometimes they back off. More often then not though, your landlord is going to increasingly become a pest until you do something about it.