If the outer shell of the vessel were spinning at a super accelerated rate of speed then I believe it would cut through space like a screw at faster than light speeds.
It would also be interesting to test, and measure light speed outside of our solar systems Oort cloud, and I believe the closest distance to exit the Oort cloud would be directly north, or south of the suns axis.
Also people need to start thinking outside the box, and stop referring to Einsteins theory's as absolutes, Einstein can think no more, but all of us can, and he did his part here when he was alive, and now it is time for us to do ours.
When examining any situations, we must look at the physics of all things involved, and the interesting thing about physics is there are so many things to consider that the ramifications of possibility's become endless when we take into consideration motion, and invisible forces, such as magnetism, sound, wave frequency's, and element compositions some of which still remain undiscovered to this day.
look for the technique, if people always look to Einsteins equation's as absolutes then they should not even study physics because they have already resigned to defeat by closing there minds to new possibility's.
Do people truly believe that Einsteins work was completed, and there are no more discovery's, I think not, If Einstein were still alive today, and with consideration given to new and updated information about our known universe I believe he would still be looking for, and finding new solutions to problems, and he would still continue to astound the people with his brilliance.
If we all do not look for the solutions to problems ourselves, and people continue to quote Einstein, then those people have closed there minds to all possibility's.
Close minded people will not find solutions.
I am going to answer your questions one at a time here in order
First of all to attain faster than light travel would not take a constant rate of acceleration indefinitely, as we would only need enough energy to take us from our point of departure to our point of destination, we should currently have the ability through hot fusion, and with regard to what we have learned through Einsteins equations that a common paper clip harbors enough energy equivalent to release the same equivalent energy in joules which is released from a one megaton nuclear bomb, then the energy needed would be provided through common mass, which would be contained with in the vessel.
Secondly there is more than one frame of thought to look at the conundrum in which at approaching near light speed the vessel in question turns to pure energy, in reverse we could examine this problem as thinking of space becoming a solid at faster accelerations, and then we would only have to treat space as a solid when approaching light speed.
Thirdly plotting an obstacle free heading would not even be necessary once we treat space as a solid, with regard to the linear acceleration of the craft in which the outer hull is in hyper quantum rotation, and in a similar way in which a tornado can drive common straw through metal without damaging the straw, your vessel would travel through matter with in our universe without damage as if solid masses were not even present.
Therefor with regard given to the linear acceleration of the vessel, and hyper quantum rotation of the outer hull structure, in which the speed of spin could be calculated based upon the density of the vessels mass then I believe that the integrity of the kinetic energy of the vessel would be conserved, and it is my belief that nothing would stop us from attaining faster than light travel through deep space.