Best exercise is going on a job site and working with a contractor line item on pricing.  

I'll also go back and tag records as the homeowners respond to my marketing so that I can see what lists are performing and what lists aren't.It does pretty much what you're describing in your post if you choose to use it in that way.

Exposure - make sure your listing is on all the main booking sites.

Their site even has a section about vacation rentals.  

Hello everyone, I’m new to this site and looking to learn how to buy my first rental. 

I’m not sharing it to criticize the site owner, but rather to highlight how small mistakes can cost you money when advertising on Google.

Am I better of just running my own rental comps instead of using the HUD User site?

I would rather take 1 year to get all zoning done on a site where no other competitors can come than to be able to build something day one with lots of comparable lots around me.  

Regularly review your property's performance, and if the ROE dips, explore ways to extract and reinvest the equity to maintain your investment momentum. 

My question is - how do I prove in the time log that I performed a particular activity?