Not to mention a markup for changing trains in Portland: you're always going to pay a certain baseline price for an accommodation no matter how far you go. Example: let's say you're going from CHI to SOB. That roomette will cost you $148 on the Capitol Limited or $162 on the Lake Shore Limited, even though you're aboard for about 90 minutes. If I did that hypothetical trip I'd consider doing PDX-SPK in coach, or even a roomette. You still get the meal and you're not really going to sleep.
Here's a sample trip for January 9, 2012 (I assume we're talking about standard bedrooms and not family bedrooms):
- Coach fare (LAX-SPK): $148
- Bedroom (LAX-PDX): $446
- Bedroom (PDX-SPK): $202 or
- Roomette (PDX-SPK): $132
I tend to assume that an included breakfast is worth $8, lunch $10 and dinner $20 when estimating costs (since I'm often traveling for business). Figure for the Coast Starlight you'll get four meals LAX-PDX: lunch, dinner, breakfast, lunch. Say $48. Throw in one wine tasting of indeterminate value (last time I was on the CS the second wine tasting occurred in Portland). Throw in a couple bucks for the free juice at TRAXX in LA. What's left is a little less than $400 for two days (albeit one night) in a private room, with access to a private first-class lounge (the parlor car). $200/day tracks fairly well with a nice hotel room, although the space and amenities are different.
The bedroom PDX-SPK is a tough sell. There's no diner, and you won't really get to sleep. No first class lounge either. From where I sit you might as well take the seat in coach and buy some food in the SSL. Save yourself $200 bucks.
There are some other economies. Baggage doesn't matter much: Delta allows three checked bags at no surcharge for First and Business Class travel. However, if you chose to do PDX-SPK in coach you wouldn't be out of pocket. If you're traveling with another person in the bedroom, you only have to pay the additional rail fare ($148), and suddenly you've almost halved the per-person cost of first-class travel. This, for me, is what really makes Amtrak attractive over long distances.
EDIT: Should have read that as SPK-LAX, not the other way round. I don't think it makes a material difference, except you get two dinners instead of two lunches on the CS.