I got bored quickly so I just did the Devanagari script by myself:
अ ा - A
छ - Ch
द - D
ए े - E
फ़ - F
ग - G
ह ः - H
ज - J
इ ि - I
ज - J
क - K
ख़ - Kh
ल - L
म ँ - M
न ं - N
ओ ो - O
क़ - Q
र ृ - R
स - S
श - Sh
त - T
थ - Th
व - V
ब - W
य - Y
ज़ - Z
झ - Zh
Some notes on the characters:
ब - This is actually the Devanagari B sound, because the writing has no sound for W and no way to change a constonant with diacritics that would alter the sound. So, I just took the B and made it the W.
examples
M'athchomaroon, okeosi anni. Hash yer dothrae chek?
मऽअथछोमरोओं ओकेओसि अणणि। हश येृ दोथृ छे क्
Anha tih krazaajaan, m'anha tih maf.
अंह तिः क्रज़ाजान म अंह तिः मफ़्
I don't like this one very much. It looks fantastic and the look definitely fits dothraki. Unfortunately, Devanagari really needs to be forced into awkward places in order to work.