They also mowed the large lawns on the garden tractor, snow blowed the long sidewalk & kept the gardens in great shape. 

I guess my fear is that there is no scaling it into an RV park, once you have one RVer interested you have a set of fixed costs that are activated (insurance, lawn maintenance, garbage and utilities). 

I'm plugging in $40/month for lawn care.

What about lawn care, snow removal, and admin/professional fees?

Typically 10-12%, unless you have a pretty big portfolio.What about water/sewer, lawn care, snow removal, and admin/professional costs.I bet you end up between $800-900/month cash flow, but that's still really solid!

Located next to a newer Walgreens, Ruby Tuesday and popular liquor store with an Applebees, Outback Steakhouse and Starbucks nearby.I was being what I feel is conservative and estimating $7,000/yr for repairs and another $10,000/yr for CapEx, plus $2,000/yr for snow/lawn care and 8% vacancy allowance or $8,200/yr.Any advice, tips or suggestions would be greatly appreciated!

Always include, even if you plan to self-manage at first.What about water/sewer, lawn care, snow removal, and admin/professional fees?

Nothing helps drive market values and rent levels than well manicured lawns, freshly painted properties, and clean streets. 

Lawn maintenance costs you can cut down on?

Then offsetting the higher rent I get for a duplex, I do have slightly higher expenses for lawn maintenance, snowplowing and trash.