I am wiring a sub panel in a pole barn that is 30 feet from the house, my questions, is I purchased a 100 amp main lug panel with 6 spaces for breakers, can I run 6-3 with ground from main panel box in house and put a 60 amp breaker in main panel box in house and use the sub panel box in barn with only 2- 20 amp beakers to run lights and receptacles , do I need a main breaker in sub panel to disconnect the power in pole barn? Also do I wire a ground rod at the sub panel?

You can use up to and no more than six circuit breakers as the REQUIRED means of disconnect for this building. Once 7 circuit breakers are needed, then one main will be required.

Yes at least one ground rod is needed. Check local codes, some states require at least two.

Otherwise your plan is fine.

Just in case, do not use NM-B cable outdoors, not allowed in wet or even damp locations.

Also, keep in mind that #6 NM cable is only good for 50A, NOT 60.

Thanks Guys, I appreciate your help I am going to work on this tomorrow.