there are two kinds of parallel signals: ONE-PART (such as "and", "or", "but"), and TWO-PART (such as "not only ... but also", "both ... and").
in the second, the part that's "locked in" by the signal and is in florida. therefore, the parallel construction would be just in nevada.
since that construction is there, the sentence is parallel:
i worked
in nevada
and
in florida.
--
for completely analogous reasons, this sentence would be fine either with or without your second "that":
an increase that
would amount to roughly five miles per gallon
and
would represent...
an increase
that would amount to roughly five miles per gallon
and
that would represent...
Why is it then that the following sentence is wrong:
I want to retire to a place WHERE
I can relax
AND
the taxes are low
Is it because the first clause begins with the word 'I' and the second begins with 'the' (parallel clauses must start with the same word)? If so, would this be okay?
I want to retire to a place WHERE
I can relax
AND
I will have the chance to play golf.