A barbell,a rack and plenty of weight is just about all you need.Also,no,isolation work is not that important
Look at this guy,who pulls and squats 700,overhead presses 300+ and benches 500 and weights a lean 230 or so.He does most of his work with a barbell and little isolation stuff
I think your best bet is training either full body or upper lower,2-4 times per week,using compound movements like squats,rows,overhead presses,pullups
531 boring but big will probably get the job done
Keeping a training log will also help,since we can help you with specific parts of your workouts.It will also help you stay consistant