Bookkeepers are fairly cheap, even good ones and should be able to setup for 2 units in a couple/few hours.  

I use QBO to keep track of my properties and do this for my bookkeeping clients also.

I don't necessarily need the standard features of pm software, such as rent collection, bookkeeping and maintenance requests, though that could help; but do need a clearinghouse of important information, such as leases, legal docs and other information; maintenance vendors I use; maintenance history; and some kind of tracking system, where I can record the various current projects I'm working on within the business.

I do my own Bookkeeping for my businesses and my clients and recommend him as a General Tax Accountant.

Besides putting together the best SOW using accurate/actual quotes as @Peter Mckernan and @Alan Asriants commented above, another key aspect is tracking expenses (bookkeeping) and monitoring the budget throughout the project. 

If our plan owned real property with many transactions, I would use a bookkeeper.

More convenient bookkeeping 

I use a CPA, too, but I like to do my own bookkeeping throughout the year and send him a tax package quarterly to review.  

I do my own bookkeeping for now and rentals are in my personal name. 

I have 30+ units and on a regular month usually only spend about 5 hours total on management things, most of which involves collecting rents and bookkeeping.