Every time you make a mortgage payment, a portion of it goes towards paying off the principal balance of your loan, which increases your equity in the property.

The rule of thumb can be useful for sizing something up to determine if it's worth investigating more. 

Generally stay away from 3 bedrooms unless they have equal size.

Here are the specifics on the unit:Large Hangar For Sale $197,500 Hangar Size: 4,125 SF (55' x 75'), Construction: Steel hangar fully insulated with efficient natural gas heat.Lot Size: 0.19 Acre (8,125 SF) of leased landZoning: AIRPORT-L, M1-L,OSPR-L, PF-L23 years remaining on land lease.Hangar has an office, shower, gas heatSingle lift hydraulic 53' x 18' door200 amp service

Once the account is size-able, then you can consider some buy and holds. 

In the meantime, we're wondering if it would make sense to (1) remodel the house to increase its size to 1100 sqft and turn it into a 3bed/2bath, (2) turn a detached garage on the parcel into a 2bed/1bath ADU and (3) build a JADU under the main house (or finish and expand the house downstairs).

Often time a lot with have a zoning stipulation that you can only build one residential dwelling on the lot, however it does depend on the size of the lot.

These regulations can specify the type of structures that can be built, the size and location of buildings, and the activities that are permitted on the property.

It's a nice town with moderately sized single family homes.

Personally, a developer bought land next to us and tried to clear a portion of our land along with his, said the line was unclear and he'd dispute it so best to let him proceed, but he backed off once he knew we had our survey and owners title and would make a claim.