Bicycle Mechanics - Will this work to replace an RSX hub/freewheel?

I was looking for a wheel and freewheel that I can use for my wife's bike on the trainer. Wanted to get something cheap (couldn't find anything cheap used), since it only will be used on teh trainer (getting the yellow Conti trainer tire). She now has RSX hubs with a 7 speed freewheel. Wanted to get something I could swap out without adjusting the RD.
Was thinking of getting these two items:
http://www.bikepartsusa.com/product_info.asp?p=01%2D142043
http://www.performancebike.com/shop/profile.cfm?SKU=15981&subcategory_ID=5130

Should that do the trick or do you need more info? Thanks

The parts will work but the only way to guarantee that you will not have to adjust the RD is to use the same hub/freewheel that's already in use.

This will work fine - the SunRace freewheel is spaced the same as Shimano 7-speed cassettes.

It's actually possible for you to, without too much effort, get the spacing of the freewheel wheel the same as the spacing of your regular wheel with RSX 7-speed freehub. You just need to move small spacers from one side of the axle to the other so that the first cog is the same distance from the drive-side dropout with both wheels. You may need to go to your LBS to pick up some 1mm or 0.5mm spacers to replace, say, a 3mm spacer which is just too large of a jump.

There should be little-to-no danger of bending the axle on the freewheel hub if you're using the wheel only on the trainer.

This will work fine - the SunRace freewheel is spaced the same as Shimano 7-speed cassettes.

It's actually possible for you to, without too much effort, get the spacing of the freewheel wheel the same as the spacing of your regular wheel with RSX 7-speed freehub. You just need to move small spacers from one side of the axle to the other so that the first cog is the same distance from the drive-side dropout with both wheels. You may need to go to your LBS to pick up some 1mm or 0.5mm spacers to replace, say, a 3mm spacer which is just too large of a jump.

There should be little-to-no danger of bending the axle on the freewheel hub if you're using the wheel only on the trainer.
I guess I didn't realize the RSX is a freehub design. Thought it was a freewheel. Is that the case on all of them? Sorry, I didn't remove the wheel yet to even check. If that's the case then I suppose I should get a freehub wheel and cassette. Though I guess what you're saying is I can replicate it with one or two spacers on the freewheel.

Shimano switched exclusively to freehubs when they went to 7-speed back in 1989 (or right around there). RSX is definitely a freehub. (Shimano has started making 7-speed freewheels in the last few years, but it's a new development and only on rather cheap bikes.)

If you're just using the extra wheel for use on the trainer, it doesn't matter whether it has a freehub or freewheel. And by spacers, I'm talking about spacers on the axle (that go between the cone and the locknut). This applies to both freewheel hubs and freehubs, but if the gears are further than they need to be from the frame's dropout, remove a spacer or two from the drive-side axle and stick them on the non-drive-side.
If you get both wheels adjusted such that they have the exact same distance between the smallest cog and the drive-side locknut, then you won't need to adjust your shifting when you switch wheels.

Shimano switched exclusively to freehubs when they went to 7-speed back in 1989 (or right around there). RSX is definitely a freehub. (Shimano has started making 7-speed freewheels in the last few years, but it's a new development and only on rather cheap bikes.)

If you're just using the extra wheel for use on the trainer, it doesn't matter whether it has a freehub or freewheel. And by spacers, I'm talking about spacers on the axle (that go between the cone and the locknut). This applies to both freewheel hubs and freehubs, but if the gears are further than they need to be from the frame's dropout, remove a spacer or two from the drive-side axle and stick them on the non-drive-side.
If you get both wheels adjusted such that they have the exact same distance between the smallest cog and the drive-side locknut, then you won't need to adjust your shifting when you switch wheels.
Got it. Thanks so much.