I think you must be overestimating costs in the US.
Flights: £300
Hotel: £30 x 14 = £420
Get a hotel near the airport so only travel costs are to from London and to from US airport. You would have higher costs in the UK.
Food is cheaper in US so again a saving.
Insurance: £20
Aircraft: 35 x 50 = £1750
If I am missing something we can add it in just let me know, at the moment it is about £50 an hour. Which is £1000 cheaper. The more hours you do the cheaper it gets. If you want links to where I got these prices let me know. You do not need a Visa if you already have a PPL.