To add to Jeffrey's comprehensive response below, another thing to consider with twin/town type homes is HOA dues. As a really rough rule of thumb, every $750 or so you spend per month translates to about $100k in home cost. So if the town/twin option coincides with, say, $300/mo HOA's then your home price budget is effectively reduced by approximately $40k.
While there are some good deals right now, time may also be on your side to see the Poway homes come down a bit further in price.
Lastly, while you are very smart to view this transaction as a long-term solution, with no children yet, you may be able to trade up in 10-12 years as the priority of your kids' education increases.
So check out both areas and maybe just weigh the priorities with a gut feeling approach.