You are right, the hardest part of making a cocaine/opium yeast would be isolating the gene and inserting into a plasmid, the actual insertion into a bacterium is almost trivial, it is done in highschool biology classes all the time.
As for sequencers, lol, don't even ask, just think HELLA EXPENSIVE. but thankfully, they are not part of the procedure, you don't need to sequence a gene to trans-plant it.
The basic sequence it this: Pulverise plant matter(leaves for coca), and do an extraction of RNA, most likely by centrifuge, use reverse transcriptase to convert the RNA back to the DNA, amplify the volume of DNA via one of many routes, use restriction enzymes to insert the DNA into a plasmid, use one of many neat tricks to insert it into yeast or bacteria, then use more neat tricks to isolate the bacteria/yeast that are expressing the wanted trait.
It sounds straight forward, and for the most part, it is. but it requires all sorts of expensive stuff, and very good/clean lab technique, which puts it out of the reach of most people. but remember, all we need it for one person to do it!!
