singitalto,
I'm glad you are going with Amtrak - you will really enjoy the experience.
As to your questions;
No, it will certainly not be boring, just the opposite in fact. Obviously you have constant scenery outside your window, and south of D.C. it gets a lot more interesting. It will be dark from about Philadelphia to Florence, SC., and this is the only time you might start looking for something to do (sleep through most of it anyway). Still, there is the lounge car for snacks and what many people find the real passtime onboard, meeting other passengers. Remember, you are not on a airplane, so get up and stroll around as the mood strikes, take pictures, use your cell phone, watch tv, and so on.
You are apparently taking the Silver Meteor, which makes 21 stops between NYC and Orlando. Each stop takes from 2-30 minutes, but most are very short. Rental cars are available at the Orlando station (you have to make arrangements in advance, I don't think they keep any vehicles at the station). Taxi's are available also. Transportation is provided to hotels, but I am unsure how this works or who operates it (Mears maybe?).
You may have to put the cooloer in checked baggage. Unless you have a sleeper reservation, passengers are asked to bring no more than two pieces of luggage per person (but there are no specific restrictions on size - unlike airlines - it just must be "of reasonable size and weight").
As to plugging in the TV, it varies from train to train - maybe car to car. Some coaches have been refurbished in recent years with conventional outlets for laptops and the like, but I will have to check if any of the Amfleet II cars (used on the Meteor) have been so equipped. All sleepers have outlets (and in-room video and audio). You must use headphones with any radio or video player. However, unless it's at night, you may not even want to use the TV/VCR anyway.
Food in the dining car is generally excellent; expect "WDW level" prices. The dishes are comparable to what you might see at Disney's full-service restaurants. If I find the website with a sample menu, I'll post it later. You will be seated at tables for four; since there are four people in your party, you won't be sharing with another party (which can be fun). Most of Amtrak's diners are recently refurbished. If you want simpler fare, head for the lounge for sandwiches and snacks.
If you have any other questions, I'll be glad to help.