Here's my
When you go into the engineering field, there are only a few career paths. And I don't think it matters whether you are in manufacturing, private practice, municpal or government.
You can stay on the technical side. I think eventually you hit a glass ceiling unless you can then be a "staff" engineer, but that's about as high as you can go.
You can move to the sales side. Either products or services. If you are in consulting, your sales or business development guys need to be able to "walk the walk" somewhat and understand what the client is looking for. As a manufacturing sales rep, you're going to be selling to engineers, so you have to know your product.
You can move into management. More administrative and HR work but still engineering related. However, you then get to deal with all of the "Bob is not showering every day and he stinks" and "Cheryl keeps clipping her nails in her cube and it's driving me nuts" and "I'll be late today because I threw a plate at my husband and now I have to take him to the ER" kinds of problems. And yes, those are all :true: that I've dealt with in the past.
You can go into Project Management. That's what I did. I knew early on that I didn't want to say on the purely technical side of things forever, so when there was an opportunity to manage multi-discipline projects, I took it. Fit well with my skills - working with clients, being organized, working with different disciplines, but not having to deal with the day to day people problems of having people report to you.
The grass is always greener - important to remember that. Every job has its own set of problems challenges. Especially when running your own business. Don't think you'll be able to go 9-5 and then forget about it. I would strongly recommend you talk to people who have their own business. Most of them will be willing to talk with you. Learn from their mistakes.
Good luck with whatever you decide!