Just do the math... remember, you pay for the room once. each person pays a fairly cheap rail fare. Each person in the room gets meals in the diner on the arm. Figure out what lodging, meals and fuel would cost if you drove. And how much time you would be traveling.
You may pay a little penalty for the fun/comfort/general great Amtrak experience.
Upsides in addition to the above...
You arrive refreshed, even bathed. No security, long lines, morons pawing through your luggage.
You are relaxed, someone else is driving.
You can get up, walk around, sit in the snack bar snooze, read, watch the scenery, have a snort (you can take your own jug aboard - just be cool), play on your computer of you must, and just kick back a little.
Downsides:
Amtrak Long Distance trains are not always on time. So if you have to be somewhere on a timeline, then fly or drive. And put up with driving, or with TSA and the general Hell which airports are nowadays.
Driving can be fun. Amtrak is funner.
I'm still sitting on a couple of million American Airlines miles, am Lifetime Executive Platinum Concierge. they treat me like royalty and I never ride in the back. But I haven't been on a plane in over 2-1/2 years. The only time I will fly nowadays is if I absolutely can't get there any other way, or to get to somewhere to get on an Amtrak.