Glad that your previous tenants left the place in great shape for you. 

This might be easier to handle between tenants.Market and Economic ConditionsMarket Fluctuations: Be prepared for potential fluctuations in the real estate market that could affect property values and rental demand.Economic Factors: Consider economic factors such as interest rates, job market conditions, and tourism trends that could impact the Tahoe area.Exit Strategy:Backup Plans: Have a backup plan in case your circumstances change, such as if you decide not to move to Tahoe or if the rental market becomes unfavorable.Sale Considerations: Understand the process and costs involved in selling the property if needed.

It's in rough shape and I am going to renovate it to bring it up to max value before I refinance it (brrrr strategy). 

. - all are occupied- 90% of properties are in rentable but rough shape and need significant work in the near future. 

I just put one property on escrow which was also in a very bad shape - strong smell with cat urine and I had to replace all drywall and existing flooring.As I am waiting for my escrow to be closed, this came into my attention.

The times I'd been over there to address repair requests (very rare throughout the years; it's understandable now) bedroom doors were closed and "friends were visiting" that day.Instead of evicting for breach of lease I decided to raise the rent by $375; they paid but sent a letter of termination with the appropriate timeline (30 days notice).The letter of termination included a statement that they fully expected to receive all of their security deposit back as they were leaving the house is "excellent" shape. 

I think it’s going to continue to trend toward the Grand Haven and Traverse City type locations over the next 5-10 years.

After six months on the market, we received no commucation nor any potential tenant inquiries which we found to be extremely strange given the good shape of the house and pricing.At last we decided to take the property back. 

I replied, asking him to send me pictures, and I would get back to him.My understanding is that if the area is in bad shape, I need to maintain it.

Make sure fourplex is in decent shape or are able to make major repairs/have funds to do so.