From tax stand point I would think you can separate from primary and be okay with IRS being that IRS will not be local code enforcement.  

However, could she gift half the property to the son who lives with her, which would allow them each to use their own separate $250k capital gain exclusion? 

I see the same (professional) Tenants coming to my Court every couple of years, with a NEW Landlord.

Here are five dangerous provisions to watch for in an Operating Agreement:Dangerous Provisions to Watch:Authority to incur debt without investor approvalPower to make loans to other entities/projectsAbility to cross-collateralize with other propertiesPermission to use investor capital for other venturesCommingling of funds across different projectsWhy These Are Potential Ponzi Indicators:• New investor funds could be used to pay existing investors• Project-to-project lending can mask poor performance• Cross-collateralization puts your investment at risk for others' failures• Commingling enables masking of financial problems• Lack of project segregation enables fraudulent schemesProtective Measures to Look For:Strict single-purpose entity requirementsProject-specific bank accountsDebt limitations and investor approval requirementsProhibited related-party lendingClear fund segregation requirementsProfessional Best Practice:Request bank statements showing separate accounts for each project.

I took the Airbnb bookings and now I'm around 80/20 Airbnb/VRBO.Based on a recent bad experience that I had with Airbnb (it's a separate thread out here), I called VRBO and asked them how I can get more booking requests from VRBO. 

That fund should have around 24,000 by the end of the year.I have a separate fund with about 130,000 invested.

Evaluate the depreciation of each item separately.

Separate issue is only 13% of CA homeowners pay for earthquake insurance because it's so expensive and the deductible can be really high.What are your re-building costs in your area?

They work, live legally, yes there existence is an illegal one but reality is deporting them, separating US born kids, it's a mess and for no real positive because they are decent legal acting people. 

I believe the investor may need a commercial loan at that point or could do 3 separate loans since they are on different parcels.