A lot of your story doesn't make sense. I can't imagine how what you describe ended up bending your AC pulley. Also, tires would have done little to prevent what you describe.
IMO, the bottom line is that until you actually DO buy the cruiser from your folks, instead of just planning to buy it, you should not be taking it off road at all.
I bought my first Cruiser when I was 16 ('78 FJ40) for $2,500 and when it broke down I fixed it as best I could with my own sweat and money. When it's your sweat and money invested, you'll approach wheeling with a whole different attitude.
IMO, the bottom line is that until you actually DO buy the cruiser from your folks, instead of just planning to buy it, you should not be taking it off road at all.
I bought my first Cruiser when I was 16 ('78 FJ40) for $2,500 and when it broke down I fixed it as best I could with my own sweat and money. When it's your sweat and money invested, you'll approach wheeling with a whole different attitude.