Custom Fields Search

Im looking to implement a ‘store locator’ into wordpress.

So far custom post types have been set up (with long and lat fields) so that is all fine.

My only question is, should I try to integrate with wordpress search by modifying the WHERE SQL or should I just create completely custom search script.

I’ve been reading the thread:

http://ww.wp.xz.cn/support/topic/different-query-multiple-custom-fields-from-postmeta-question

But the solution just isn’t working for me and it seems fairly resource intensive.

Is there a simpler way of doing this?