Too many questions to fully answer.

I would suggest you do your own research on the Internet .

Prices for Global pass on Intrrail site. Allow for reservations especially for Eurostar to London.

Train planning is personal choice but use several planners. Day trains, night trains, long day and connection times. Also have backups for delays or missed trains.

I would guess you would need at least 3 days each way. It may be possible in 2 long days but you would spend most of it on trains or on stations.

Hotels and food costs etc.

If you are only going to London I  would  fly. 

If it is your first trip to London please note it is expensive for any centre hotel.

If you want to tour the UK  then you could get a global pass

Best site-and Yorkie should very well know that: is seat61.com.

This is by Mark Smith, former manager of a very big LONdon station, real fan of trains, he has set up this site to describe all ways of overland travel to all countries in EUR, mostly by train, but also other means of needed. It is not specific for passes, but will give advice. He also often appears on the general touristy forum tripadvisor.com, apparently he has noted that the usual responders here do know their stuff.

And yes-flying will be much cheaper and faster (Certainly on those cheap TR airlines like Pegasus and Anadolu).

IF done by train-the fastest (in the time that the single direct car Ist-Bucuresti runs-summer only) is 3 nights plus most of day 4 after. THis is without breaks, unless just changing trains.

Much Appreciated for the reply. Gonna check it right away.

Thanks for the reply. I’m going to stay at a homestay in bournemouth but planning to travel some countries before i get there. 

Good luck with your planning. Feel free to use the community for help.