I have skied Vallter many times in the last 5 years as I have friends in Camprodon & Setcases. The drive up to the ski area will take about 40 mins from Camprodon (hardly ski in ski out) but the views down the valley as you reach the higher parts of the road, outweigh the length of the drive. You will need chains in the snowier times.
The beginner slopes have quite a large right to left camber & in my opinion are difficult to learn on if you are a beginner. There are two ways to get to the top of the mountain, either by chair lift or by the much quicker drag lift. I for one like to keep my legs so I take the chair. Once at the top on a clear day the coast of the Cost Blanca can be seen, which is always a bonus when sipping your hot wine in the hut. For the best run down the mountain stick to the right. This will lead you down through a narrow wooded area & you will have to take an old 2 man chair (bit tight if you are the larger skier) back up to the main ski area & car parks.
Miss the weekends completely as the Barcelonians arrive here in droves & the car parks are full by a very early time in the morning. Needless to say the queues are massive at the weekend. If you are here for a week then take Saturday as your day trip to Barcelona as they are all in the mountains.

Resorts that are close & worth a one day visit are La Monina & Nuria. Currently not on Snow-Forcast, Nuria is interesting as you can only get there by funicular railway from Ribes De Freser but the ski area is very small an not good if you are a complete beginner.