The sale price will most likely be around $500,000 and the mortgage is currently about $200,000.I plan on using the profits (let’s just say $300,000) to build an ADU on property that my family owns in Central Oregon.

Do your homework, build a team, and avoid analysis paralysis.  

There are several different kinds of exchanges with different rules and timelines, not just one type.

You can purchase a lot to build a home.

I am still pretty new to the area but I am ready to jump in and start investing in multi-families in the Albany and surrounding areas.  Since this is something that is best done with a team of experts that know a lot ...

In a very loose rule-of-thumb estimate, your Net Income (revenue minus expense) may be about 50~60% of the gross revenue. 

Each town has different rules regarding rent control. 

Understand the multi-family market, scale up portfolio efficiently, focus on value-add opportunities, build a reliable team, stay informed, and engage with the community for support.Good luck!

Rule of thumb: I've been told "Never fall in love with a property".

One golden rule I follow,if it takes a long time to fix/replace when it breaks, don't buy a cheap one.Imagine, this thing breaks in the middle of your peak season and the people who can come out to rebuild are 2 weeks out....It takes at least a day or two to build something like this even if you are super skilled.