You could always store those columns within a jagged array, an array of arrays. The syntax is actually pretty easy in VBA; you can store all the .Values of a range (in the form of an array) inside of another (previously dimmed) array. 
When you're working with a range that includes several sub-ranges (contiguous or not), you can access them separately by looping on that range's .Areas property.
The only thing that you have to be careful about is the indices because the syntax is a little funky and in your particular example you don't start with the first row.
Option Explicit
Sub NonContiguousRanges()
    Dim rng As Range
    Set rng = Range("C2:C20, G2:G20, J2:J20, T2:T20")
    Dim jagged As Variant
    ReDim jagged(1 To rng.areas.count)
    Dim i As Long
    For i = 1 To rng.areas.count
        jagged(i) = rng.areas(i).Value2
    Next i
    '=-~ examples of accessing the values ~-='
    'first value, C2
    MsgBox jagged(1)(1, 1)
    'last  value, T20
    MsgBox jagged(4)(19, 1)
    MsgBox jagged(UBound(jagged))(UBound(jagged(UBound(jagged))), 1)
End Sub
I mean just look at all those UBounds... gave me a bit of a headache just getting it right!