Here’s a link to some PA44 documents I’ve put together. This includes the Carenado docs, plus a 1978-80 POH (that seems to match exactly), and a POH for the Autopilot, Transponder, and ADF.
Little known feature alert: The transponder has an OAT and Density Altitude readout, just hit the function button until the right window comes up. Probably more accurate than the thing sticking out of the windscreen, and knowing the DA can be handy during summer months.
The documents are here.