And the IRS can look at an installment contract (which that is) and deem it a "sale" right up front and force him to pay taxes on the next gain.

The prices in and around the city of Charleston have skyrocketed, which is forcing a lot of people to expand outward ( down I-26).

The type of heating fuel (oil, gas, etc) will also have an impact on the rentability of the property.Also make sure you are covered from a snow/ice slip and fall standpoint.

I don't want to force them to move, but I feel I must make some adjustments to rent rates as well as talk to my insurance agency.

Also watch out for rules that would impact your tenancy i.e. no rentals with short term leases or leases less than 2 years, or no renting out individual rooms, or no rentals to individuals with different last names.  

I am willing to sacrifice convenience – and also some money – if it has a big impact on my ability to qualify for a mortgage in 18 months.  

@Jorge Rodriguez@Brandon Hall has given you some good insight into your issue and I think you should also consider the impact of renting the house out.

With only about an acre of land, however, owning the minerals rights will not make a large impact on the price when buying or selling within an area that is not currently being developed.

Is it having a significant impact by inflating prices, or is it fairly minimal?

They remediated their tank but one of the surrounding neighbors was leaking and they couldn't find exactly which one and couldn't force neighbors to test so they still don't have a No Further Action letter from NJ DEP.