Additionally, it has a boat lift on a river that leads to the ocean, a 3 car garage, and extra land with RV connections already in place.

To estimate appreciation, I currently use the general inflation benchmark as a baseline, with a few extra point for the Bay Area.As far as the exact appreciation percentage per year, that is not something we can control or accurately predict.My gut feeling is that higher inflation will translate into higher appreciation.

Taxes are mostly pass through so your added expense is mostly LLC filing fees and extra tax preparation expense for all the entities.

Because I bought the property a while back, it still became a good deal with the appreciating market, however, this was an unplanned expense that put extra financial pressure on my life.

An extra payment every year will shave 7 years off.

I didn’t know of house hacking at the time but I figured the extra income from the ADU would be really helpful. 

Her and my dad own an extra lot next door and the neighbor asked if they could use the driveway until they had a chance to put in their own drive.

If you buy your own home, seek to pay it off ASAP first before buying the next investment (a safe, low risk path,) or use that extra savings to put a down payment for the next rental?

Adding an extra $500-600/mo in property tax makes a huge difference. 

I am trying to avoid transitioning from a construction loan to a traditional mortgage to avoid any extra fees.