Followers of the sakhī-bhāva make a distinction between Vrindavan, Vraja and the Kunja, as is clearly stated in these verses:
rādhā-kṛṣṇau khelataḥ svāli-juṣṭau ||
Only there in Radha’s flower grove cottage,
and nowhere else,
the embodiment of infinitely wondrous mutual love,
the descent of beauty, form and expertise in the arts of love,
engaged in eternal, uninterrupted,
and deeply intoxicating love games,
the Divine Couple of Radha and Krishna,
plays, accompanied by their sakhis. (1.10)
In this and the two previous verses, Prabodhananda Saraswatipada shows his predilection for the mood of the Rādhāvallabhi Sampradāya, of which he must be considered a founding member. Some of the differences with other rasika sampradāyas are discussed here.
Where the Dhām is concerned, those who call themselves followers of the sakhī-bhāva make a distinction between Vrindavan, Vraja and the Kunja, as is clearly stated in these verses, starting with 1.7. The development is given beginning with the standard Upanishad (Mandukya) hierarchy of four stages of consciousness culminating in the turīya state sought for by the Advaitavadins, i.e. Brahman. This is where Prabodhananda, as a sannyasi from Kashi, would have begun his spiritual journey.
Higher than that is Vaikuntha, and the various Dhams of Krishna līlā–Dvaraka,/ Mathura, and Vrindavan.
However, Prabodhananda makes a further distinction between Vrindavan, where Krishna’s parents and vātsalya-rasa are dominant, and Vraja, where Krishna engages in his pastimes with the other cowherds and the cows. Where those pastimes are present, Radha and Krishna’s most intimate līlās cannot take place. Therefore those following the sakhī-bhāva have conceived of an abode of the Lord that is exclusively dedicated to the madhura-līlā. This is usually called the Kunja.
Since the Kunja is only possible where Radha and Krishna are present, and where Radha has no competitors, the sakhī-bhāva sampradāyas even consider līlās like the Rāsa to be a part of the Vraja and not the Kunja.
A similar hierarchy can be found in Gaudiya Vaishnavism in the Upadeśāmṛta of Rupa Goswami, which leads to Radha Kund as the most intimate or most secret portion of Vrindavan.
vaikuṇṭhāj janito varā madhupurī tatrāpi rāsotsavād
vṛndāraṇyam udāra-pāṇi-ramaṇāt tatrāpi govardhanaḥ |
rādhā-kuṇḍam ihāpi gokula-pateḥ premāmṛtāplāvanāt
kuryād asya virājato giritaṭe sevāṁ vivekī na kaḥ ||
The holy place known as Madhupuri (Mathura) is superior to Vaikuntha, because the Lord appeared there. Superior to Mathura is the transcendental forest of Vrindavan, because of Krishna’s rāsa-līlā. And superior to Vrindavan is Govardhan, for it was raised by Krishna’s divine hand and was the site of various loving pastimes. And, above all these, Radha Kund stands supreme, for it is overflooded with the ambrosial nectarean prem of the Lord of Gokula. Where, then, is that intelligent person who is unwilling to serve this divine Radha Kund, which is situated at the foot of Govardhan Hill? (Upadeśāmṛta 9)
Though the words are somewhat different, the principle is the same. In the Kunja, Srimati Radharani is most clearly manifest in her svādhīna-bhartṛkā svarūpa. The mood is that of the nitya-vihāra, where Radha and Krishna are never separated for a moment. There is no viraha. Though Prabodhananda as a sādhaka may express separation from his divine mistress Radha, he never writes of her separation from Krishna.
śrī-rādhā-mādhavayor yathā kadācin na sambhavo virahaḥ |
tad-rasa-vṛndāvanayos tathaiva paramo’vinā-bhāvaḥ ||
Just as it is impossible for Shri Shri Radha and Madhava to ever be separated, so in the very same way their rasa and Vrindavan cannot exist independently of each other. (VMA 12.2)
Thus it is established that Radha’s kunja and the Divine Couple’s nitya-vihāra are the centerpoint of the Dham. To enter here is the prerogative of the sakhis and no one else, and in particular those sakhis who follow in the footsteps of Rupa Manjari.
vṛndāraṇya-maheśvarīṁ priyatayā yās toṣayanti priyāḥ
prāṇa-preṣṭha-sakhī-kulād api kilāsaṅkocitā bhūmikāḥ
keli-bhūmiṣu rūpa-mañjarī-mukhās tā dāsikāḥ saṁśraye
I take shelter of Shri Radhika’s handmaids, headed by Rūpa Manjari, who always please their beloved Empress of Vrindavan by offering her betel-leaves, massaging her feet, bringing water and arranging for her meeting with Krishna. These handmaids are even more free from any shyness or retinence than the prāṇa-preṣṭha-sakhīs [like Lalita] even in times of her most intimate play! (Vraja-vilāsa-stava 38 by Raghunath Das Goswami).
VMA 1.9 : Radhika’s cottage in the kunj
VMA 1.8 : Vrindavan contains all the Dhams
VMA 1.7 : Vrindavan includes all of Braj
VMA 1.6 : What is it to me if you cannot see Vrindavan’s glories?
VMA 1.5 : Take shelter of Vrindavan with all your being
VMA 1.4 : Where all the relishable relationships are found
VMA 1.3 : O Vrindavan! Reveal your true essence to my heart
VMA 1.2 : A humble determination to glorify the Dham
VMA 1.1 : Mangalacharana: Radha Krishna, Gauranga and the Devotees