I'm a fan of balancing with front panniers, but if you need space and want to use a tagalong-style, I really can't recommend the Roland add + bike highly enough. The rear rack is heavy, but the attachment is designed to make full use of the top & sides for touring (and the tagalong itself can come with a rack for your kiddo's gear). That's what I use when touring with my daughter; if you're in the US bike24.com will ship very reasonably; I think it still ends up being about the same as buying the Burley tagalong even here in-country.