I am looking to do similar and am in the process of educating myself on Japanese Real Estate to do some multi-family investing (to house hack at first, and grow a portfolio beyond). 

I have an IRA (used to be a 401k from another previous employer several years ago) which I use with an Edward Jones retirement strategist to help it grow over the next 20+ years. 

You want to focus on the market (growing pop/jobs > natl avg);  deal (conservative underwriting, simple value add plan) and experienced  teams.  

Expenses growing is part of the game, nothing is static. 

I see a lot of younger people on the site which I think is outstanding as I am jumping in at the tender age of 60.

Yes the property does get the mortgage and such paid (a slight loss each month, but just increased the rent so for the short term renter we have we are making a positive cash flow, but only for a few more months).I will definitely be asking questions and trying to get our portfolio growing. 

Certainly you could go all cash and certainly some investors recommend this but you will not grow your wealth nearly as fast as if you used leverage though it will be much safer.

@Kyle Ferguson @Thomas S. is spot on about making saving, clearing debt and growing your wealth a priority with your significant other.

I have had as rentals, and back when I was that age lived in places that were 3/1.5 and it worked fine. 

The invested money was to help the company grow and expand it's reach.