>>Or would we be able to us it on the next ferry with space available<<

Yes. But it's a good idea to give CalMac a quick call as far in advance as you can if you get held up. In my experience they are very accommodating.

What Gordon_R said. Summer sailings (especially on weekends) may be full so you might have to wait more for than one. Ringing ahead may get you a firm booking on the later sailing.

Thanks for the tip on ringing ahead. It will be a Tuesday in August and we;'re hoping to make the 3:15 crossing.

We had a Hertz rental thru Auto Europe in Glasgow. We picked it up at the Marriott and it was very easy to get on the roadway that led out of town (saw signs for Stirling so assume it was the same direction we went.) We had no trouble at all -- it was a weekday ~10-11 am.

Thanks yestravel. We opted for airport pick up (EDI) and drop off (GLA). Usually I would not do that, but in this case, the airports seem close enough and access is easy.

The two airports are the very easiest places to pick up and drop cars so you made a good choice.

Have a great trip! I loved the little we saw of Scotland.