(1) taruya
sono ookisa taruya, sono gen ni haete iru ki ga suppori osamatte, ..
taruya is an old expression (but is still used especially in literature).
taru = to + aru: meaning strong assertion of "being".
ya = to emphasize one's feeling, to attract attention
taruya = as to ___ (when one is talking about something remarkable)
So this expression (taruya) is used to convey the speaker's strong feeling (in case of the sentence you quoted, maybe speaker's surprise), to emphasize the predicate (something being gigantic).
sono ookisa taruya,
sougen ni haete iru ki ga suppori osamatte, ...
(その大きさたるや、草原に生えている木がすっぽりと収まって...)
It's so huge, the whole tree in the field could fit in...
(2) reino
rei (例) means example, standard, custom, etc.
Literal translation of 例の reino is "in question".
We use it to refer to something known/understood well by both the speaker and the listener, without mentioning clearly what exactly it is.
So "reino" can be translated into "you-know-what/who".
When one says 例の通り "rei no toori", it means "as usual" and the "usual" state is being understood between the speaker and the listener.
Hope this helps.