Touring through Spain Oct 1-12. Having the option of going to Gibralter and Morocco(Tetouan) for the day. Being from So. Calif, is this similar to going to Tijuana for the day? No one has really raved about it. What would be a better alternative?

Gibraltar is one of this places that looks good from far away, Rock Shape in between continents. The closer you get the worst.
If you want to go to Tetouan for a day
you have to take the ferry in Algeciras and then a bus. There are travel agencies offering this trip. Which I think should be the best choice, otherwise you are going to spend a lot of time going through border formalities.

I did both Gibralter And Morocco . Gibralter is a nice half day trip. If you go take the taxi tour to the top of the rock.You will see St Michaels cave and the Famous Winston Churchill monkeys Get a fish and chips lunch in a British pub. There is lots of duty free shopping. The Morocco tour if you take a organized tour you take the ferry then you are picked up by a bus .It is like as you say going to Tijuana. But the salesmen will follow you all over the place .It was like Disneyland Ride three men escourt you thru the streets. and on que you run in to a snake charmer for a photo op .Then they take you to lunch at there friends Restaurant where you will see the uglyest belly dancer in the world. From there you go to a carpet shop where no one leaves till someone buys a carpet. Then to a local spice shop .You Get some free time shopping in one of there friends stores.Finally on to a Camel ride / Photo op a few miles away .all the street vendors that you thought you left behind followed the bus in cars to make one last sales pitch before you get back on the ferry it is a very long day 7am to 8pm you have to catch the earliest Ferry in the AM.One last note on Gibralter try to Park on the Spain side. Tt is much faster than waiting in the customs lines to get back into Spain.

the comparison of tetouan with tijuana is pretty valid. both are two of the filtiest, seediest places i've been.

you won't really get a good impression of morocco from tetouan (or tangiers, for that matter). if you can spend a night, try at least to get to casablanca.

CarlaM
Sorry I forgot the last part of your message. And a better alternative is not to go.
Morocco is a great country, but you need to get to Xaouen,Fez,Meknes, to appreciate. just like mexico and Tijuana but with arabs.