Hi,
There is lots to do in Salou and most of it you can do by yourself (without going with reps) When you get there find the Tourist info places, there are a few of them so im sure you wont have a problem finding one. They will give you a map and be able to tell you about the bus services and trains. When you are walking around the resort you will see that there are some offices in the streets where you can book the likes of jeep safaris, quad biking and other stuff.

Buses that run through the resort will take you to La Pineda where you will find a waterpark with dolphin shows (aquapolis) there is also a market here behind the waterpark on a friday.
Tarragona, this also has markets on a tuesday and thursday (i think), it also has old roman ruins, a modern town centre and a lovely beach.
Cambrills, this is a old fishing village not far from salou, it has lots of shops and gives a taste of "real spain"
You can also get the bus to Port Aventura from resort or you can walk its not too far away.
There are other places to go too, i think that you can get a bus that takes you to Barcelona, you can definately get the Train but you will have to check the times especially for the return and also the Train can get really packed.
Im sure you will enjoy it whatever you decide to do,
have a good hol.
Lou.

There was definately a service bus running to Barcelona this summer....

And I agree with Loulou about checking the trains - they DO get crowded and the last one back IS early.

When we were there 2 yrs ago we had the chance of tickets to see a Barcelona game at the Nou Camp but found we wouldn't have been able to get back to Salou after the game
Apart from what Loulou has mentioned the shops around Salou offering excursions have some that go further afield that you wouldnt be able to DIY such as Andorra and Montserrat.

At the harbour there are different boat trips on offer ranging from a short trip to Cambrils if you dont fancy the bus (which can get crowded) to full day trips.

A great day out is the Jeep Safari Can be booked at the shops or with reps at hotel.