Generally a good strategy. Buying a house now as owner occupied will get you better terms than you can ever get buy buying a rental after buying an owner occ.

Also, if you buy the first house as a primary now and convert to a rental in a couple years you can take advantage of the tax credits for 1st time buyers currently available.

Also, if you are focused on a property that makes sense as a rental, you will buy smarter, with less downside, since you will insist on break even or positive cash flow. You will likely be more conservative than most people would when buying a personal residence.

The downside when you buy your personal residence is that lenders typically count 75% of the rental property income when figuring DTI levels. Again, this will reduce the amount you can pay for your personal residence. There is a silver lining in this, it keeps you from stretching too far on the primary.

As for the cash. It makes sense to put 20% down to get the best rates on the first house.