Is there any way i can customized my campaign IDs, or give my campaign ids in a sequence? or do I need to create a custom field and mark it as a campaign number or ID and put the numbers as per the requirement? Also, in either case what should be the best practice for data flow in CRM?
Unfortunately you can not define the specific program ID as you create programs/campaigns. As you already alluded, you'd have to create a custom filed and populate that per your requirements.
What is the exact need for syncing the campaign ID over to your CRM? Would need to know more to add my comments!