6MF. The in-between level of an Abrupt Elevation change does not get multiplied by in-hex terrain, nor does it increase for hexside TEM or Artificial Terrain. Terrain is only factored in during the final level entered. See B10.51 plus the B19.4 EXample.
So 2MF for the first level change plus 4 to make the second level change while entering the jungle/woods. If there was also a hedge crossed, the total would be increase by one (+7).
If SMOKE was being entered, that SMOKE would simply add 1 MF, also only to the final level calculation (B.2 and B10.51). So again: 2MF (1st level change) + 4MF (2nd level change) +1 for SMOKE. Note, this is an exception to the normal rule for Artificial Terrain which is usually added to COT before multiplying by 2 for a single-level change (so 4MF or 2x2 to ascend 1 level through SMOKE; 6MF to ascend 1 level through woods plus SMOKE).
And you CAN advance here
If your unmarked by CX, you get a CX for advance into difficult terrain (cause no one has 6MF in advance.... 4 or all is your choices)
If your already CX you have to go somewhere else (that is less than 4 or all)
which happens a LOT in PTO/Jungle scenarios BTW