Depending on your physical dexterity, two days (16 hours) is a fair estimate for your first time at a fan motor.
Most of that will be spent dealing with unfamiliar assemblies. Caution is needed with plastic bits - they are old now, and may break.
Finding all the clips around both sides of the HVAC housing is the most challenging part. There are fan turbines on each side of the HVAC - don't mix up the left and right. The clips on each are hard to do the first time, but once you teach yourself the trick, it's easy.
IMHO, the job is made easier by removing the glovebox, steering wheel, stalks, and instrument cluster - doing so allows you easier access to the demister ducts connections on both sides of the outer layer of the HVAC outer housing.
From experience of both, a 240 heater fan R&R is about 27 times less hassle than changing a 960 heater core.
