(Light?) rust removal from chain Situation:
I'm new to the world of trike maintenance. My son and I purchased recumbent trikes at the end of last summer. The weather for the past couple of months has been cold, snowy, cold, and...cold (Northern Pennsylvania climate.) So I cleaned them, tried my hand at lubricating the chains for the third time since owning them, and put them up in the shed to keep them out of the sun and precipitation.

This weekend looks like the first time in awhile that we might be able to go for a ride without freezing the fingers off. I took a look at the trikes, anticipating having to add air to tires and maybe clean the disc brakes, and saw the chains:

The top is one trike, the bottom two are the other...

On soliciting some info, I was told that is "definitely rust." Apparently I didn't do something right when I put them in the shed for a month of storage, or rust is not easy to fend off. As I said, I'm new to this, and trying to improve maintenance skills. I'm hoping this isn't so bad that the chains require removal or replacement at this point.

Questions:


How bad in shape are these chains, relatively speaking?  
I have yet to find a definitive answer to this; how do I clear off the rust? WD-40, followed by degreaser and relubricate them?
These are chains that came stock with the trikes. I wonder if the future fix is to get a particular type of rust-resistant chain?


Being winter in PA, the roads will no doubt be salty from road melt material. I'm trying to keep the trikes cleaned, touch up paint where chips are found, wipe them down, etc...but there's a lot of contradictory advice on how to do certain things. Any advice/fixes for the questions above would be appreciated...
As long, as you can easily move the links of your chain, there's no problem. Just lube them and ride them, and they'll be fine. The movement will rub any rust from the critical places. You may need to work the chain for a while before the links become free, a creeping oil should help get the links moving again.

That said, there are two ways to ensure that a chain won't rust (as quickly as yours):


Make sure they are always well-lubed. A surface that's covered by oil is not covered by humid air, and cannot rust. May work well during storage, not so well when you actually use the bike.
Use chains with an anti-rust coating. I have quite good experiences with this, though the chains are a bit more expensive. I'm not sure how robust the anti-rust coating is against sliding through a front deraileur, though (I only ride IGH). In any case, I've never had a rust-proof chain go stiff.

Of course, anti-rust coated chains still like being kept well-lubed...