Yep! just like to help out. You should check out the most Recent model railroader, it has comparisons for most DCC starter sets out there. Its worth a look
It looks like the superchief set does have a walk around throttle. The only difference is that the premium is radio equipped. The regular requires you to install terminals throughout your layout to plug into. Its not that annoying to keep up with the train, and your current layout doesn't really justify the extra cost of a radio controlled hand held throttle. You can always buy the radio transmitter later if you need radio control.
Again, i think you should reconsider. Look at it this way: You're not even finished with your current layout. By the time you finish this layout to any appreciable degree, its going to be a few years from now. It also seems like you have space problems as it is! If your profile is accurate, you're also 18, which means you'll probably be heading off to college soon, if you aren't already.
By the time "the future" rolls around, the super-chief set is going to be outdated, and surpassed by other systems. This is why i suggest that for now, you stick to system that fits your current needs, because that big layout you're dreaming about isn't in all likelihood going to be coming down the line any time soon.
In regards the perfomance of the DCC system, Its not that you can only run 3-4 trains, you can run as many as you want realistically. What i am saying though, is that again, your needs don't currently demand that much capacity, and its not worth the extra costs. Besides, you can always upgrade to a higher system when the time comes. There is no use in locking yourself into something that will be potentially outdated, and that costs more than what you should have to pay.
Those are some good prices, but like i said, i still think you're paying way more than you should be. You are gaining very little in the grand scheme of things. The system offers higher maximum current to handle lots of locomotives, which may be good in your case. However, when you consider that upgrading the power to your layout is not an expensive proposition, it hardly justifies the cost of buying such a large system.
Whats more, when you compare the Superchief to other DCC systems in it's class, it still falls short. Its not worth it for your application.
If you really want a large system comparable to the Super chief, there are a few systems i'd reccomend over it.
I'll get NCE's option out of the way first, because to be fair, there are several other manufactures out there that also field competing products.
the NCE PH Pro R Is almost exactly the same as the Superchief. There are only three notable differences. One, It has it's own 5 amp power supply, which works for you. It is only capable of handling 60 cabs, while the super chief can handle 120. To me though, I HIGHLY doubt there is a layout out there today that needs that many cabs, and by then, they probably need a bigger system to handle that many trains. The other difference is that the NCE system can handle 29 functions, while the super chief is shockingly limited to only 14. This in my opinion should sink the digitrax system. its already becoming outdated!
Here it is. the description on the site is totally correct-
http://fiferhobbysu770.corecommerce.com/DCC-Systems/NCE-NCE-0001-PH-Pro-DCC-Set-p13425.html
There are cheaper options such as the Lenz Sets 90 and 100. they also have a 5 amp maximum current, and also need a power supply. In addition, they can only host 31 individual cabs, but again, unless you're building a club layout that will have 31 people running trains, its not relevant. an interesting plus is that they have a 10 year warranty, and feature a computer interface that can allow you to turn a PDA into a handheld wireless cab. They also feature 29 functions, and walk around throttles are available.
the only difference between the Lenz set 90 and the 100 is that the lenz 90 set is MSRP $300, and it comes with a more basic throttle that handles running the trains and basic programming. This throttle is meant more as an "operator's" throttle, with a speed control knob, but less buttons. The Lenz Set 100 is $400, but it has a larger "master" throttle that is capable of doing more programming, (and as such, it has traded in it's knob for speed control buttons).
The lenz 100 set. the other set is even cheaper, around $248 on that fifer site.
http://fiferhobbysu770.corecommerce.com/DCC-Systems/Lenz-SET-100-p13610.html
In the end, you can probably find the lenz systems that do all the same things and more than the super chief but for less money.