I'm fixing up my dad's old road bike and have come across 2 problems that I'm a little baffled by.

1) sometimes the cranks slip under load. what I mean is when pedaling up a hill, there will be 1 or 2 revolutions of the pedal that suddenly have much less resistance and do not propel the wheel at all. Does this mean the crank is stripping? or something wrong with the rear wheel? any ideas? I took it home and tried to replicate it but couldn't get it to do it again.

2) when the chain is in the smaller chainring and the largest cog (easiest gear) the rear derailler is stretched out so it is almost straight, it looks like it is too far (though I don't really know how far is too far, it just looks funny). so i was thinking "maybe i need to add a few links so that doesn't happen, or slide the wheel farther forward in the dropouts". But I shifted into the larger chainring and the smallest cog to see what that looked like, and the derailler arm is sucked up against the chain on the smallest cog, routing the chain against itself and creating lots of noise and resistance.

Nothing on this bike has been changed in a long time, it's been running great for years. Any help is much appreciated

Oh by the way it is a Ross Gran Tour XII unknown year.