Since I don't fly too much, I've never been one to really go all in to learning the rules etc for every airline.
So I have some limited knowledge about United and I was hoping that others could share their expertise.

I'll be flying to U.K (London) in September for a month and as far as I can see, these are my options.

EWR-LHR . United. 60k Economy roundtrip.
100k Business. No saver availability.

BOS-DUB. Aer Lingus. 25k Economy
50k Business.

My final destination is Leicester. And I could fly from Dublin to East Midlands for about 50 Euros and it's so much closer to Leicester.

Actually either way would work...I'd be spending the same amount of $$ from London to Leicester as I would from Dublin to East Midlands to Leicester.
But on the flip side, I was planning on visiting Ireland either way, so therefore I could do it at the start of the trip...

Are there any other cheap options that I don't know about?

I live in Hartford, and therefore would prefer United, because I could get a stopover and therefore add BDL into the mix for free.

But I'm just a novice and would appreciate your expert suggestions/help.

EDIT: One thing that I forgot to mention. I will probably have two bags with me and if I want to avoid paying a king's ransom for the second one, I'll have to take that into consideration while choosing my flight.