This "movx @R0,A" with uCs ALE connected to SJA1000s ALE do the timing and demultiplexing of the register adress and data for you. But beside /RD and /WR you need a proper /CS timing.

If X is the select signal for the CAN chip:

/CS = ( /RD or X ) or ( /WR or X )
( -> one 7432, not 7402!)

If a "handswitched" port pin is not what you want why not map CAN to the next higher 128 XRAM adresses? By the way, on my controller boards I use a standard 64k EPROM as an adress decoder. An easy way to get 8 free programmable decoder outputs without any CPLD stuff.