If you do not have a crystal ball it is wisest to get your tenants acustom to annual rent increases.

@Christopher MontgomeryI wish I had a crystal ball to help!

It's not reasonable that you as a FTHB could/should have known all of that above, someone in the chain of professionals should have been more clear on what the property is and isn't before you even got into escrow... typically the listing agent is the one who dropped the ball (ie, if they called it a "triplex with one vacant unit ready for an owner occupant!"

Player throws the ball all the way up court, attempting an impossible shot.

I know what I want to accomplish in this and know what direction I want to go just hard to get the ball rolling.

Here are some possible answers:Immediately before an area re-gentrifiesAt the bottom of the market, but any time before the top of the market can work.When a good purchase opportunity presents itselfMy view is that #3 is something that can be determined without a crystal ball. 

Bring someone who has enough experience to give you a ball park number.  

Now if you are sending a low ball because you want to make your numbers work or that's what you want then it could be an issue.

Low ball offer or come up with an agreement and put 20% down2.

It's very hard to spit ball numbers on any type of development project because every town has different restrictions and every site within each town is unique.