Good luck with the transition, each airline is slightly different from what i hear. I cant comment on the long haul side of things. My employer will pay for your accommodation and give you duty pay and an allowance for food during initial training. Some dont.
They reimburse me my annual medical but i have to do it on a day off and pay my own travel. No home to duty travel, they expect you to make your own way to the place of work. And report time generally means at the crew room, so you have to factor parking up, maybe a bus then getting through security etc.
But they will pay for all travel and hotels etc when you are required to be out of base. We get a duty payment for every hour on duty and if we overnight an additional payment on top. So an overnight would be 24hrs of duty pay for instance.
If they give you a hire car you are expected to refuel it and claim the money back. Any mileage if you choose to use your own car (for us) is at quite a low pence per mile rate, but you can reclaim so extra via your tax return.
All these allowances will attract a certain amount of tax, only introduced within the last 2yrs or so.
If you want to chat please drop me a PM.