Wow. I could go on about this all day...lol
First, see if there is a spare 220 plug at your breaker box. If so your in like flinn, run it to the trailer and seperate the two live wires. Each are 120v. and30 amp pull and will be pleanty. if not, no problem. what ever you do, make sure you DO NOT "hang the extention cord in the air. lay it on the ground or even better, burry it an inch or two. You will need a charcol filter!! The 200 bucks will save you 2 years of jail time. as for lights and equipment. I would use 3 gallon buckets or five gallon buckets. The space should allow for 3 rooms. your cuts room only needs two 4 foot florescent tube fixtures. Use plant life or daylight full spectrum tubes. Your vegg room can consist of a 400 watt ballast with a metal halide bulb. Your flower room can have a 600 watt ballast and a sodium bulb. the space should allow for about 10 plants in flower from your best 12 in vegg, from your best 16 to 20 cuts. The cuts from the vegging plants and go in to the cuts room, mature cuts in the vegg room, mature vegg plant in the flower room....etc.. You could pull a pound cured every 60 days If the conditions, temp, stain and care all are good. remember all 3 rooms need to be free from sharing any light with each other. You also need room to work in the trailer. Have you considerd using the trailer for flower only and maybe advanced vegging while keeping a grow closet in the house for cuts/starts? Your chances of infestation are greater in the old trailer than in the house and if a problem exist's and you need to teardown/ resetup and deepclean to get rid of bugs, you know your restarting with healthy well kept cuts.