By far, the best part of the experience proved to be the friendliness and helpfulness of both my coworkers in addition to my manager.
What I wish was different
Partially due to the government contract nature and the generally older employees, many had families. Having a family meant that many coworkers had their children off school for summer and took extended breaks during my internship. The lead frontend dev was only working for the first few weeks of my internship and I only wish I could have learned more from him.
Speak up about your opinion on design decisions and always get as much constructive feedback as possible, it helped me loads.