A first-gen unit isn't, other than the view out of the front, any good as an "observation car" anyway, the windows tended to be quite small, particularly on Met Camms.
Another one I've heard is setting up as a mobile bar for music performances and similar, for which the low-back seats will work well.
It does help that a Pacer is shaped quite like a 1st gen unit - 3 windows at the cab end and short vehicles. 143s and 144s even more so, with the high arched roofline inside (similar to a Mk1) and the outside body not looking like a Leyland National.
Paint it green and kids will think it's Daisy.
FWIW, sadly this unit has now been scrapped (there's a horrible picture of it being cut up if you search, I can't quite bear to post it here given how rare 141s are), but this looks heritage:
141103 at the Weardale Railway in better times - Wikimedia Commons
Travel kettles, love it