Which CRM is best for ME?

I am an independent Manufactures Rep.; Salesman. Using Office 365 on my Microsoft Surface Pro 4 and Windows 10. I have used ACT! for many years but not for several years and I am looking of a CRM. I need it to fully function without an Internet connection when traveling but would like to back up the data when in range of an internet connection. ONE USER...ME. FYI I am in the Chicago area and travel IL, IN and WI.