Cat Walking - Short-term Flea and Tick Protection?

My husband and I would like to take our indoor-only cats out for the
occasional wander. I know about harnesses and walking jackets, but I
would rather not use something like Advantage if we only take them out
a few times a week during good weather.

I've read some unpleasant things about the toxicity of flea collars,
and I don't know if flea mousses and powders are any better.

Can anyone recommend safe, effective short term flea and tick
protection?

--
Jennifer