I arranged a trip last season for myself and my 2 nephews.
Booked it all seperately but that was because I had access to 2 tickets via a season ticket holder. Still had to get a third ticket from the club directly and that was a struggle but did get one. I think it was the first or second home match vs West Ham. Depending on demand, some tickets do go on general release but this means ringing the ticket office and if you are lucky and eventually get through, you will then be on hold for ages and if you need more than 1 ticket, you will be doing well to get them together. But again it depends on the match i.e. opposition. After the big spending on players, you can be sure tickets will be hard got !
Flew into Manchester quite cheaply with good old ryanair and got the train over to Liverpool. Went for 2 nights and did the Anfield musuem and stadium tour and of course the souvenir shop. Had a great time and maybe did it for 200 euro max each. With 3 we were able to share a family room in the hotel.
But to be honest, you should be able to get a package for 300 or less and if so I would go with it. The only thing I guess is the longer journey but when everything is arranged for you, it certainly gives you peace of mind.
Loads of travel agents do them - I think the Sunday Wolrd carry a load of ads every weekend.
I go over to the UK a few times a year for rugby and football and book it all seperatley well in advance and one of these days I will get caught with a fixture change but so far so good !!