Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

Nice to meet you.

For me as well as the seller.First, you have to define Sub to financing.Do you mean the reckless kind where you overpay for a property, take over the financing and borrow from others to cover closing costs and holding costs when you have no money, no credit, no income, no reserves and can't tell a warranty deed from a deed of trust and you close on the kitchen counteror do you meanbuying below market value, already having a nice income, having reserves, using escrow and title, already understanding the due on sale clause, have done a lot of creative purchases and know when to use and when not to use creative finance and how to recover if something goes amiss?

It could be a nice opportunity however I would be certain they will want you to make up the difference between $250,000 and whatever is left on the mortgage which btw in my opinion should be done with lender's knowledge and approval. 

It is the most popular software in the industry and all CPAs know how to navigate it which is nice.

Once you have completed the consolidation portion of your 1031 exchange you now own a more expensive (and probably really nice) property that it must be your intent to hold for investment use. 

Appliances look nice until the pet hair destroys the fan on your nice stainless steel fridge and you are out another $1k+ to replace it... 

Philly is a nice option, but you have to study the blocks for about a year to be sure you understand the area you are investing in.

Another nice bonus of using this as a funding source is no closing costs, big help on the front end.Obviously, if all goes relatively well, the plan would be to hold these properties as rentals and refi at some point down the road when rates on mortgages drops back down a bit, whenever that may be.

It would be nice to know the opinion of other experienced investors in Japan.