How do i know if this is a 5 day calf strain or one that could keep me out for up to 12 weeks?

Can you describe the strain? do you just have pain in the calf? where at, is it a sharp pain?

Most likely it is something that you can work out by massaging the calf. I highly recommend you pick up a copy of the trigger point workbook.

Lefty,
It is very difficult to predict whether this is a 5 day or 5 week scenerio. In my experience most people can be back to running moderately in 5 days with the rest(cross train), stretch, ice, massage approach. It is usually when you try to add speed work, sprints or hit a longer distance in that it can come back and bite you.
If you are committed to get this fully recovered I like to progress thru an eccentric calf exercise where you lower over a step on the injured leg then use both to come back to the top position. The emphasis is on controlled lowering, not raising. Work up to 30 reps (after the pain is gone with light running) then progress to holding dumbells - up to 25#. Jumping rope is also quite helpful to restore the quick contraction ability. Try 20 double leg, 20 left, 20 right; then 30, 40, 50 etc.
You can find the calf exercises and stretches on the new DVD if you would like some visual on the exercises. You can also find a section on cross training approaches at The Injured Runner web site.

I have bookmarked the recommended books you have mentioned here--what a great resource! I am particularly interested in the trigger point stuff, as my poor body is really having muscle tightness/tension issues especially in my neck and upper shoulders--I would call it chronic. My daughter (11 yrs) is experiencing some achilles pain due to her sudden increase in running. (fall soccer!)

I'm excited to look into these--thanks! :D