Salaried work can feel like one is been taken advantage of it most of the time one is working 50 or 60 hours a week with out additional remuneration. In my experience there has been business cycles of busy and quite times, and while one was expected to be there for the busy times, I made sure to relax a bit during the quite times.
Does it always balance out? No, but you can be damn sure I didn't arrive to work early if I'd been up half the night working a problem. And the one time I was in work till 4am, the next day I got sign-off to use a local hotel should it happen again.

In your case you may not feel you have such leverage. Maine isn't exactly IT Mecca, but neither do you want to cut your nose off to spite your face. If you push to hard can you afford to lose the job? Your boss is likely been pushed to bring you and your friend's wages down, moving you from 50-70 hours a week to salary does that, you just need to insure that the salary that you are offered is fair. Does Maine require time and a half for hourly workers for time worked over 40 hours?

In any case, I would look back at what they have been paying you for the past 4 months and use that as a starting point. But this likely means cutting your small business clients in the area. If you are not willing to loose these clients, then you need to figure what you are willing to give of your time to this company. This can be a set number of hours per week, on-call support (which could be paid per incident, time per incident or waiting by the phone time) and a another agreement for times that they need/want to send you Florida.

Given that the company is growing you want to ask your self if you want to grow with it. Not talking about stock options here, but rather career path. Does continuing to work at this company provide you with some good options? Or will you always be expected to be a jack of all trades, master of none and smile about it?

On the subject of travel, the policy will vary greatly from company to company and from rank to rank. Typically the company is going to pick up all your expenses, and pay you as if you were at the office, hourly in your current case and yes if you were salaried there would be an expectation that you work your ass off to get the project done in the allotted time. So flights, hotel, car hire and meals should all be covered. They should also be covering millage to the airport and airport parking costs. How they cover these is going to vary, some will expect you to pay for everything, and submit and expense report with receipts for every cent and will cut you a check in a few months, again it varies.

Good luck Randall.