Ted has to go straight to the base...they are the ones that came out in 2014 and they are HIS VOTERS.
What will be interesting to watch is how The Establishment teams with the Democrats to try to win Primaries with cross-over voters, as they did in Mississippi. They will NEVER defeat Cruz with just Republican voters.
From the Wikipedia article Open Primaries in the United States
States with an open presidential primary
Alabama
Arizona (Semi-closed, with primaries open only to unaffiliated or unrepresented voters)
Arkansas
Georgia
Hawaii (Open primary for state, local, and congressional races; caucus system for presidential races.)
Illinois
Massachusetts (All races' primaries open for "unenrolled"/unaffiliated voters only)
Michigan
Minnesota
Mississippi
Missouri
New Hampshire
North Carolina
North Dakota
South Carolina
Tennessee
Texas
Vermont
Virginia
Wisconsin