Welcome to the forum!!
1) CLEP Macroeconomics and Microeconomics are both very doable. They are not the easiest CLEP tests, but they are also nothing to be afraid of. It sure beats sitting through a semester-long college course.
2) Take Macro first because it will give you the overall big picture of economics, and it's a little easier than Micro.
3) IC is very helpful. I also supplemented IC with the Barron's book for Macro. And I used the
Cracking the AP Economics Exam book for Micro. I also watched the
Standard Deviants videos, which were somewhat helpful. All of these materials I borrowed from the library.
I do not recommend the REA guide for CLEP Macroeconomics because it is far too vague, in my opinion.
And use the Peterson's practice exams to help gauge when you are ready to take the actual test.
