Captiva Canoe and Kayak has rental at McCarthy's Marina at the foot [bay side] of Andy Rosse Lane.
Captiva has got the best restaurants, but some are pretty good, usually. All of these are in the tiny village area:
Bubble Room - this place has fascinating decor and the food is mediocre. The desserts are the best part of the meal and you can get them for take away, which is what I do. Frankly, I don't think you get your money's worth, but the kids would like it, so try it for lunch.
RC Otter's does breakfast best and it's a nice very low key kind of place. Stick with simple food.
Key Lime Bistro - across the street from the Mucky Duck and same owner. This is more 'upscale' but still casual. Food quality if inconsistent.
Mucky Duck - At the beach end of Andy Rosse Lane this English pub type place used to be one of the better places to eat but the food isn't as good as it used to be. The fried grouper sandwich is my favorite. And the Ice Cream Brownie Sundae for dessert. Skip the shrimp dishes. Live entertainment most nights outside and THE sunset place.
Cantina Captiva - on Captiva Dr this is also owned by same person as Otter's and Key Lime. Mexican, but chain quality.
Sunshine Seafood Cafe - Captiva Dr again same owner as Otter's et al. Small and upscale and pricey. Not the best choice with kids.
Starbuck's - coffe and tea [I like the Iced Tea Lemonade with Passion Berry fruit tea] and dry and rather tasteless pastries.
Green Flash - Bayside at the south end of the village area, this bayfront restaurant has good, reliable food and killer bay views.
Queenie's - at McCarthy's - Ice cream
Latte Da - coffee and food to go on Andy Rosse Land
Captiva Island Store - some take out, beer, wine, deli
Just south of the village at Tween Waters Inn are:
Old Captiva House - fine dining, upscale and the best food on Captiva. Pricey and not formal, but maybe more than you want with 3 young children.
Crow's Nest Bar - bar food light meals and on Monday's and Thursday's they run NASCRAB races that are great fun. The early show is for families and the 9PM is adult.
Down at Blind Pass bridge just as you hit Sanibel are:
Sunset Grill - Reliable choice B,L,D with some Gulf views. Good spot.
Lazy Flamingo - very casual bar style food. No table service, you just pick it up and seat yourselves.
Mad Hatters - tiny and very upscale gourmet type place. Very expensive. It's too small for a large group and really an adult dining type place. Chef owned.
About 5 miles further down San-Cap is Doc Ford's - casual and one of my favorites. Kind of latin spin on the food, but just an all around solid choice at fair prices and good with families. Very popular with locals.