Iṣṭikāpatha is mentioned in the Rājataraṅgiṇī 3.467 (see here) and was identified by M. A. Stein with the modern village of Ramaradan. This is almost certainly not the place mentioned by the author of the Rogārogavāda and some scribes of manuscripts in the Panjab (-DW)
Grierson, Modern Vernacular Literature of Hindustan (1889), entry
#476, p.105, refers to a Madhusūdana Dāsa, a Māthura Brāhmaṇa of
Iṣṭakāpurī. B. 1782 AD. "He translated the Rāmāśvamedha into the
Blumhardt (1889), entry #65, p. 43, notes the same author,
Madhusūdana Dāsa, and the same work, Rāmāśvamedha. Blum. says it is
a metrical translation of a portion of the Pātālakhaṇḍa or fourth
book of the Padmapurāṇa. He notes that the author says he was the son
of Rāmacaraṇa of Iṣkāpur, near the river Kalindra, and that the work
was written in 1773 CE. Blum. refers to Grierson's note on the name
of the town. Blum says the poem is in the Baiswari dialect.
Baiswari is (WP) the same as Awadhi, spoken in Oudh and Nepal,
though speakers are also found in MP, Bihar and Delhi. ("the
language of the tract lying between Bareilly to Allahabad, north of
the Yamuna river and south of Mahabharat range in Nepal, cornered by
Etawah in south-east and Khalilabad of Basti Janpad in northeast."