Just explain that costs rise each year and that this is necessary to keep the property in good condition.

Constructed in about 1970, building in OK condition. 

They've since paid voiding the eviction but I expect we'll need to do it again next month. sigh...One piece of advice is to make sure the rent is appropriate for the condition of the unit. ie, if it would rent for $1200 fully renovated, what's it worth in its present condition.

But the conditions surrounding this acquisition were a lot different than the two homes I had purchased in the past. 

There's a huge % of our country which votes to give up more of their privacy and freedom every time they're given a ballot whether or not it's in their best interest because doing so typically has some "feel good" gift wrap so we find ourselves in a tough situation as social media/tech/business/finance/foreign interests collide under these conditions. 

Determine a base rent on current market conditions, supply, etc. and add on based on my unit and amenities.

Ideally looking to keep the house as my primary residence for at least a few years, then either use as a rental or sell depending on market conditions. 

These are the terms of the contract which I would offer:$20k - Option fee$2100 - monthly rent, $450 of which goes toward equity at the time of purchase.Buyer / tenant on the hook for all maintenance from day 1.2-year lease term.Sale price is fixed up front according to 2-year value projection (present market conditions).

You'll have to judge whether the condition of the car is worth all this work, legal fees if any, and getting the car into working condition. 

what is the water piping, drains, electric, sewer and heating system condition?