Like I mentioned before x64 isn't my strong suit so I need a bit of assistance with this one.
Titanfall 2 has
*VPK
*RPAK
*STARPAK
VPK fileformat hasn't changed since TitanFall 1 it still uses the modifed Valve format with lzham
compression.
RPAK contains a header which has a string to the starpak that contains the contents of its data
0x67 bytes in.
image base: 0x7FEE2880000
sub_7FEE28831C0((__int64)&v43, 257i64, (__int64)"r2\\paks\\Win64\\%s", (__int64)v5);
is used to combine the paths to form a full path to the data
so for example.
paks\Win64\mp_homestead_loadscreen.rpak
contains starpak
paks\Win64\pc_all.starpak
sub_180008C80 inside rtech_game.dll loads the paks
Hooking ReadFile also points to rtech_game
Rtech DLL
http://cra0.net/rel/rtech_game.dll
Samples
http://cra0.net/rel/tf2_pak_samples.zip