I set aside 15% for CapEx, Vacancy, and Repairs/Maintenance combined. 

I will be setting some stakes for the driveway of a 5 unit MHP soon and plan to use that to expand out to some other places thereafter on my own land.

Thing is, I know auctions all have their own set of rules and such.

I use OwnerRez. it is nice to set up email triggers, templates, create a direct booking website. it does integrate with Pricelabs and also has integration with other platforms besides VRBO and Airbnb. 

Recommend you improve on it instead of just asking for a referral.Without setting proper expectations, you will typically be disappointed.

You just have to know how to set them up to avoid issues on the future UW/fundings.

Any insight from the resident experts on the best software to use to streamline management for a small set of MTR and STR (total 3 right now)?

Instead of giving advice, I rather share facts (there are many opinions but only one set of facts) and I'm trying to help you come to your own conclusions.With this in mind, if I were you, I'd ask myself the following questions:1.

What is you opinion on setting up LLC and other aspects of this business first.

Not this intrinsic RTP ratio, but if the area is growing, there are limited infill lots, vacant lots nearby are priced higher than others areas relatively.