If you use a mortgage calculator, a 6.5% fixed 30 yr mortgage for 180K (300K house minus 120K downpayment) with 1% property tax ends up at a montly payment of $1362. Add insurance and HOA and Mello Roos to that depending on what you buy. A 5% interest rate starts you off at $1191 principal + interest + tax.
$2000 is about 32% of your gross monthly income, which is what many consider to be a maximum amount. 25% puts you at $1562. So yeah, $300K seems reasonably affordable if you find a place with no or low extras, particularly if you have all of your ducks in a row (sounds like you do) and reasonable potential for income growth.
