I'd rather spend a bit more, and install six 40-gallon heaters, separate out the hot-water lines and electric or gas to each rental unit, and let the tenant's pay for their own hot water. 

If it is outdoors, and the intent was to shut off gas to the neighbor for some reason (possibly a safety issue such as exhaust from some gas appliance not done properly), then the gas company should be able to put a lock on the neighbor's meter so as to not affect others.Now, if the problem is due to a gas pipe leak somewhere before it reaches the meter, then a shut off at the street is the thing the gas company has to do - but then they should also repair things.

But she has to use her own car, buy her own gas, to drive people around to do showings.

We removed a large maple tree in the middle of the non existent driveway, expanded the curb cut, paved the driveway, excavated and graded the overgrown back yard, put a new roof and siding on both the the house and garage, new garage door, new garage door opener, all new electric, all new plumbing, new HVAC, new HW Heater, opened up the floor plan, all new appliances, new kitchen, new hardwood floors on 1st floor, added a 1/2 bath, converted a bedroom into an en suite master bath, installed a basement waterproofing system, brought gas to the property and more. 

I'll elaborate a littleExamples:  Natural gas hot airNatural gas hot waterOil hot waterOil hot airElectric baseboardElectric heat pumpPropane hot airPropane hot waterAs an overall, the first is what provides the actual heat, the second part is how it gets delivered around the house.Natural Gas Hot Air:  Generally there is a furnace that heats the air and has a blower, and then air ducts that deliver the hot air around the house.Natural Gas Hot Water:  Now it is a boiler that uses natural gas to heat the water (separate from the domestic hot water for your shower) and then circulating pumps that move the hot water through baseboard pipe units with "fins" for distributing the heat.Oil just uses that fuel (instead of natural gas) to either heat the air or the hot water. 

I live in Oklahoma so no issues.I have seen wall mounted vent free heaters work as well but you will have to run gas to it. http://www.homedepot.com/p/Dyna-Glo-30-000-BTU-Blue-Flame-Vent-Free-Natural-Gas-Wall-Heater-BF30NMDG/206556618

I have no gas to the building, so I can't help you there.

You should connect with the all the utilities, water, sewer, electric and gas to determine what services are available to the property you are considering and what the cost will be to make it into a build able lot.

I removed the property management cost since I would be doing that, and increase the electric and gas to reflect what I would be paying (I'd be splitting utilities with my roommate).

New roof & siding on the house and garage, new garage door, new garage door opener, all new HVAC, complete house re-wire, all new plumbing, new hw heater, brought gas to the property, all new deck, new hardwood flooring on the first floor, all new interior/exterior doors/slider, overgrown back yard excavation, curb cut expansion, maple tree removal from in front of garage, new driveway, termite treatment, basement waterproofing system, basement wall reinforcement, and new footings since we open up the floor plan and vaulted a ceiling.