Potty training Jax did not take terribly long either for me but like poster above, I was lucky to be off on winter break from college so had a good 4 weeks to get him on a schedule. It was really hard work at first. But it paid off in the long run. He was about 95% reliable by 6 months. He is almost 5 and hasn't had an accident in... forever *knock on wood* The only times I remember in the past few years were during bad rain storms, etc, I would sometimes find poop off in the living room. But that hasn't happened in probably 2 years.
I did do the crate training at first but it honestly did not last long. The first night I let him sleep in my bed was the first night he slept thru the night.
The rest, as they say, is history... but I do not think 3-4 hours is bad at all to be left in a crate. 4 hrs is probably the max I would do at THAT age, but it should be fine.
Personally, I think potty pads and outdoor training can be confusing. It CAN be done for sure, but I think sometimes it just confuses the dog. You are saying it's okay to pee in the house, but only in one spot, and potty pad trained dogs often mistake rugs for pads. I don't think it will cause any harm though to have a pad and an ex-pen set up initially. That way at least you are giving the option if you think one day he will be left for long hours.
Basically it boils down to your wants, and your lifestyle. Jackson is free roam in the house, I always knew he would be and that was the ultimate goal. Luckily he always proved to be reliable when I was not home so it wasn't an issue. Some dogs will always have to be crated or in an expen, it really just depends.
I also knew I wanted him to be able to sleep in because, well, I like to sleep in when I can... so as a puppy (since I was off), I would get up with him around 7am, potty, we would play for 20 mins or so, and then I would bring him back into bed. At first I would just put him back in the crate ON my bed with me, so he got that I was going back to bed for a bit. Now he will gladly sleep in with me until 10 or 11 lol. But yeah again that was something I wanted my dog to get used to. So I think you just learn what you want, and what you find acceptable, and you will get into a rhythm and groove.