Character mistake: When John and Judy are running from the Robots he shouts "Run Penny!" even though Penny is not there. (00:34:21)
Shell Game - S2-E9
Revealing mistake: While Maureen and John are piloting their two maintenance pods, in the closeups which face each of them head-on, note the walls behind them have numerous identical smudges in their individual pods, which is especially noticeable in consecutive closeups.
Continuity mistake: When Will introduces Robot to Gypsy, in the following shots Gypsy's blaze changes shape, revealing different horses portray Gypsy.
Continuity mistake: When Judy is talking with Victor Chariot 8 is on the right side of the C19, then it is on the left side almost immediately.
Answer: Yes to all questions. The best theoretical estimate is that the universe is about 7 trillion light years across. That is about 250 times larger than the currently observable universe. So, yes, using trillions of light years as a unit of measure is appropriate. And, yes, the age of the universe is a measure of time, and the space between galaxies is a measure of distance.