If you have more than a unit or two, Excel becomes too cumbersome to maintain. 

The parks that simply rent the lots to homeowners and do not maintain the homes lead to much fewer maintenance and management costs than apartment or single family home investments.

I maintain the asset and pushed up rents.  

I do this because I manage and maintain all my own properties at this time.

Would it be best to maintain the personal account for that other cabin and continue paying bills as we have, and then just have the LLC take a property management fee each month?  

Inexpensive, looks good, easy to maintain and clean and wears better than anything I have found.  

Retail Lessees pay out the nose, are responsible for NNN charges for improvements that they  don't control, and often pay additional rents based on breakpoints-- BUT the Owner has to be able and willing to make all the top-tier improvements and maintain the property at the highest level for the sake of the general public who will visit this merchant.  

To increase cash flow you will need to turn over tenants every 2-3 years to maintain rents at market rate. 

You're not responsible for fixing every little thing, you're responsible for providing a habitable place and getting things fixed as needed to maintain that.Helpful hint, charge extra per mo and get a weekly or at least biweekly maid to keep up the common spaces.

Plus your rentals should cash flow enough to maintain cash if rents should lower due to the economy.