Thanks for your comment, Allan.

You appear to be referring to a Schwarzschild black hole which – as you’ve noted – is not ordinarily traversable.

Many physicists including Stephen Hawking and Kip Thorne have theorised that traversable wormholes can be established through the use of exotic matter.

Still others such as Homer Ellis, K.A Bronnikov, and Matt Visser have shown that there are types of traversable wormholes that are allowable solutions in line with general relativity.

Regarding mass increasing as you approach the speed of light – true, however perhaps we need not reach C itself. Moving at speeds at significant percentages of the speed of light (say 0.1C or 0.3C) still lets you experience some effects of time dialation…albeit a fraction of it.