A few years ago base was fine to join...
Then Casa said 3 legs must be flown...
Now we are back to base joining...
IMHO joining anywhere in the cct can be dangerous given the wrong circumstances and lack of understanding, communication and airmanship.
As long as your situationally aware of the aircraft around you and communicate you can join via an inverted, oblique, sideways, loop the loop special leg.
Unfortunately with a ctaf or ala some "pilots" couldn't organise a piss up in a brewery and flounder away with no communication, airmanship or regard for anyone or anything.
Keep your eyes peeled and thinking the way your thinking (safety aspects and how to fly safer) and you will do great!!