We spent 3 nites in Monterrosso and loved it! We took the bus from base to Aversa ,then took the train direct from Aversa to La Spezia 1st class for about 60E per adult ticket; 30E for kids. If you are a party of 6, it's worth it to have your own 1st class compartment with comfy seats and power plugs for the 6 hour train ride. Once in La Spazia, pick up a train to the CT towns, they run about every 20 minutes or so.
After doing extensive online resarch, we chose to stay in Monterrosso and hike/train to the other towns. It was perfect for us as Monterrosso is the only CT town that has two large beaches for the kids; and lots of wide, flat open walking areas for the grandma with bad knees. And, personally I just like that town the best, but opinions vary!
We used tripadvisor.com to find a b & b, and were very pleased with La Poesia. You can read my review, as well as others', on tripadvisor.
We ate out at three restaurants in Monterrosso: DJ Pizza, Via Venti, and Restaurant De Ely, and all were fabulous. DJ Pizza had wonderful fresh lasagne and fantastic fried anchovies; Via Venti had great ravioli and desserts; and De Ely had the best pizza I've ever eaten, great seafood, and the best desserts. You'll be offered local CT wine whereever you go. I didn't think it was all that great, and kind of pricey. But the food prices were surprisingly reasonable, on par with here locally.
If you plan on hiking the trail and using the train, it's worth it to get the rail/trail pass to save time and money. If you buy individual rail passes, remember to get them validated as we did not, and learned the hard way that it is a 50E fine for each ticket that is not validated! Aside from the train and trail, there is also a water ferry that goes from town to town, and a bus. We took the ferry out to the point and back and it made for a nice afternoon.
The trail from Riagamorre to Manorola is paved and flat-perfect for kids, strollers, wheelchairs etc. The rest of the trails are steep steps, narrow trails, and very rocky. Not good for young kids or those with bad joints. But the views........!
If you don't care about swimming then April is a great time to go, before it gets too crowded. I hear it's a zoo in the summer, but that crystal blue water looked oh so tempting!
I highly recommend this trip for those looking for a taste of small-town coastal Italy. It's easy to meander the side streets away from the touristy areas and really enjoy the atmosphere. Visiting family will love it, and there is something for everyone there. Hike, shop, or sit in the piazza and take it all in.