15 year mtg or cash for next place?

[Charles M.]

Hi I am looking for advise, I am having a hard time weighing out these two options and making a decision. 

Option 1 - 15 yr loan
refi my current 230K 4.375% 30 yr loan by putting in 70K and getting a 160K 15yr loan at 2.8 apr. 
This lowers my monthly by $100 and pays my mortgage off 25 years faster (im 5 yrs into my current) and I would save 100K on interest payments

Option 2 - get rental #2 
refi at 230K at 3.5 apr and have 70K cash (and growing) ready to buy another rental or two when prices fall.
This keeps my mortgage the same, just lowers my monthly payment by $200. 
It seems like a bubble right now and in a few years It would be a good time to get a second rental

My objective here is too make the smartest/most logical move and build wealth, not to proudly say I have (only) 1 rental that is paid off, which my family is advising to do.

Although I like the idea of a 15 year, id hate to miss out on a future fall in prices/implosion because I didn't have free'd up cash, which I think is coming in possibly a few years.