Nat GasPE-- Before I would submit the termination letter, I would gut it out another 6 months, with your new license in hand at the old firm. I would see how things go-- going in business today is tough-- it is not as easy as it seems. If you have a great "book of business" and think that some of them will follow you to your new business, great. However, that does not always seem to happen. I would develop a rich pro forma before you get started-- you may have done all of this already and are ready to jump, however, as one who counsels lots of small business owners-- gut it out another 6 months, saving every dime you can acquire while you get set up.
You can buy office furniture used, desk, chair, credenza-- no problem. You will need good computer equipment and a color printer. You will need some stationery, cards and promotional material as well as legal start up expenses and some office supplies. Get all of this set up BEFORE you pull the pin. Perhaps you have done all this already, however, if you have not, it will take you 2 months to get going, 3 or 4 if you move to a new location.
You will find that you are the guy for everything-- the trash, the coffee, the accounting/bookkeeping, the advertising, etc. There is no staff, just you. Now, if you have several good accounts initially and can afford to have staff, great. However, that is not the case for most folks going on their own the first time. This is more challenging than it looks, not impossible, however, more challenging than you imagine.
Just some ideas to consider if you have not done so.