ちょうどいいね。新型の試乗してってもらうね。

。。

Perfect timing. I'll have you take the new model for a test drive.

Literal

Just-right [ね]. New-model [gen-の] test-ride do-go-[receive-favor-もらう] [ね].

してって is a casual spoken contraction of していって — the て-form of する + いく, expressing a 'do-then-go' action. ~てもらう marks the speaker receiving a favor from the listener: 'I'll have you do X for me.' Combined, してってもらう = 'I'll have [you] do [it] and go.' ちょうどいい is a super-common compound adjective 'just right, perfect.'