You are correct about alternative locations, my first iteration had the PRT & plumbing under the spare wheel well at the front. I moved it to the accepted location due to what I considered to be an age before the temperature was up to normal. There was a lot of cutting, changing, shortening lengthening & joining, I ended up being surrounded by bits of scrap rubber, probably sufficient to keep a johnny factory going for a day or so. All that had to be replaced & the mad octopus of PRT pipework had to be acquired.
It still takes longer to get up to temperature than if it were left standard.
M