Prioritizing of tasks vs context
I don't think GTD wants you to prioritize by Context. I also don't think there is any problem with jumping from Context list to Context list.
Some reminders:
* Separating into Contexts was to keep us from "blowing a fuse" whenever we saw our jumbo Next Actions list.
* Separating into Contexts was for an efficiency factor as well. In deciding what you should do at a given moment, the first question is "What CAN you do?" It doesn't help you to review @Errands when you have 5 minutes in between meetings, for example, so there is no reason to review them.
* A Context is the "critical location or tool required to perform that Next Action". (Therefore, if you are at your home office, you may be @Home, @Phone, @Computer, @Office, etc., all at the same time.)
You could choose to have no Context lists. You would then only look in one place for Next Actions. However, you would have to read through many Next Actions that you can't perform, because you aren't in the Context for them. You end up having to do a second of thinking--can I do this here?--for each action. On the other hand, it's nice to have one big list because you review it more often than you may review a given Context list.
Or, you could choose to have Context lists. You would then have to determine what are all of your current Contexts when you review your lists. This may require a few seconds of thinking, like in the home office example above. I find, for instance, that "@Anywhere" is the easiest child to neglect, so to speak. On the other hand, if you know you are going to be at a phone, it's nice to have all of your calls on an @Phone list.
This doesn't give a definitive answer, but I hope it helps you figure out what works best for you.
JohnV474