"I will go there at two o'clock."
This was a complete guess for me. Hadn't seen そちら before, and I had only heard of へ being used for vague directions.
What's the big difference between そこで / そこに and そちら?
そこ and そちら mean about the same thing (there). However, the nuance of そちら can show direction (that way). In addition, I would say そこ feels closer to oneself and そちら is much further away.
そちらにつきました。＝＞He arrived there.
そちらは暑いですか。＝＞Is it hot over there?
そちらのてんきはどうですか。＝＞How is the weather over there?
そこについた。＝＞He arrived there.
そこは夏だ。＝＞It is summer there.
そこのみせです。＝＞It is that store over there.
There is a difference between which particles（の・は・に・で・へ）you add to a word.
に and へ can both mean "to" when used.
「Hokkaidoへ行く」 and 「Hokkaidoに行く」 both mean I will go to Hokkaido. The difference is that the へ emphasizes direction (going towards Hokkaido) and the に emphasizes the destination (going to Hokkaido).
These ideas can be transferred to when you use そこ and そちら.
そちらへ行く・そこに行く＝＞I will come over (i.e. I will go over there). Technically they are different, but the English will be the same.
に and へ can often be used interchangeably, but not always. In other instances you can only use one of the two.
で shows that you will be completing an action at the place.
そこで会おう。＝＞Let's meet there.
そちらで食べましょう。＝＞Shall we eat there?
You would be meeting or eating at the location, so で is used.
All of them are subtle differences.
まで - going up to the place
に - going to the place
へ - going in the direction to the place
草津まで行きます - Going up to Kusatsu, where it can stop at any points until Kusatsu e.g. it can stop at 京都
草津に行きます - Going (directly) to Kusatsu, and normally it won't stop in the middle.
草津へ行きます - Going in the direction of Kusatsu. Normally it means the same as に but the emphasis is the direction rather than the destination.