How tough/easy is to crack a 787 type rating course? Is a wide body aircraft difficult to fly especially when you are transitioning from 737? Any tips/suggestions would be much appreciated.
Biggest things here are going to be the availability of training courses as well as full motion simulators to do the training in. There are a lot of FMS systems for 737 aircraft operated by multiple companies offering type ratings in that airplane. Conversely I only know of a few companies that offer initial and recurrent type rating work in a 787. Boeing offers a type rating course in this aircraft, and as well as the individual 787 operators have their own initial and recurrent type rating training.
Your ease of obtaining a type rating is largely going to be a function of how big your bank account is. You will also have to select whether you want to receive an initial type rating as a first officer on 787 or as a captain of the 787. The training will probably take 3-4 weeks and approximately 20 to 30 hours of sim time (you will never fly the real thing for a type rating) to complete in a full motion simulator, and those are costing roughly 1000 dollars an hour to operate. So at that time requirement plus say 2000 dollars for the course cost of materials, you're probably looking at around 22,000-32,000 USD, provided of course you pass the check ride at the end. If you were new to jets or other fast movers, this would probably be a monumental task for you. If you have been type rated already in another airplane like the 737 or similar, the process should not be very difficult.
On top of that, unless you're going to go immediately fly for a 787 operator somewhere, that type rating is pretty much useless. (If you don't already have 4000 hours TT plus at least 1500 PIC Jet time, don't even bother applying; no airline would hire you for that role, type rated on the jet or not). And it's only good for 12 months; you'll then be required to undergo a recurrent type rating as either a first officer captain on the 787 and will cost about 60% what the initial type rating did.