I think the premise itself is a bit hard to accomplish, although far from impossible. Czechoslovak authorities' fears that the Soviets would annex Slovakia and Stalin's own views on national identity, and the strength of the local Communists - on top of the Red Army's presence - all made it harder for Prague to hold on it. (See: Seeking Peace in the Wake of War. Europe, 1943-1947)
But assuming this did not happen. The Czechoslovak Constitution of 1920 already - in theory - granted Ruthenia a great deal of autonomy, including its own legislature and a directly-elected Governor, as well as the right to its own symbols and the use of Russian/Rusyn/Ukrainian in all administrative and public functions. Now in practice, unit 1938 most of these provisions are not actually implented.
The Diet was treated like any other county/land assembly and governed as such by laws from Prague, and although the Governor did exist, most of its powers were taken over by the Prague-appointed Land Administrator.
The interesting thing here is the impact that an autonomous Ruthenia would have on the reividications of Slovaks, which were not really taken on board by the Communists after taking power in 1948 until 1968. Even if under Communist rule, Ruthenia remains an autonomous area, that will upset further the balance of power in Czechoslovakia.
In terms of local impact, Czechoslovak authorities during the inter-war period, greatly supported mass education and development of sanitary conditions, electricity and generally the modernisation of cities and the countryside. In general, I don't think it was a bad period for the region, which living conditions and education levels raising fast. HOWEVER, Czechoslovak authorities sent a lot of Czech-speaking civil servants to run the region.
While it was always the understanding of Ruthenian elites that as there were not enough university-educated Ruthenians to run the region, by the late 30s, Czechs still continued to run the region despite some timid efforts to recruit more locals. Uzhorod could easily end up as a Czech-speaking island in Ruthenia.
In religious terms, yes, Czechoslovak authorities favoured the Eastern Orthodox Church over the Greek Catholic Church, as it was of the belief - not wholly wrong - that a great deal of the Greek Catholic priesthood was pro-Hungarian. My understanding (but don't quote me on this) it's that by the late 30s, postures had relaxed as new priests were running the Greek Catholic Church, which adopted a far more neutral note on the state issue.
Identity-wise, that's the fun part. When you exclude the Communists and the Czechoslovak parties (only the Agrarians would have mattered) the political issue of the time was Ukrainophilia versus Russophilia. Czechoslovak authorities first favoured the latter, then 'Rusyn-philia' (to little success).
The division between these two camps ran deep within most aspects of the region. Different grammar books, different schools, different reference authors, different threates, etc. Almost churches too, as the Greek Catholic Church was very split between the different factions. The Eastern Orthodox one was not, it was Russophilic. In 1938, there was a referendum on which grammar book to use in schools, a Russian-based one or a Ukrainian-based one. The former won, but not convincingly enough to put an end to the divisions. They will remain there.
In fact, in a non-Soviet Ruthenia, these issues will remain at the forefront of regional politics. During the brief democratic period of the Third Czechoslovak Republic (1945-48), I am curious as to what kind of parties may appear. No doubt a Communist Party of Ruthenia would exist, apart from either the KSČ or the KSS, but the question is what other party. With the Agrarians banned under the Kosič programme, and the other parties (ČSDSD, ČSNS, ČSL) barely existing in the region, I would not be surprised if a bunch of former agrarian voters end up voting Communist. The remaining ones, I suppose might vote ČSNS if better off and more urban.
It's likely at least one party, à la DSS, would be allowed to be formed to represent the right-wing of society, but I would expect said party to be fairly divided by the same Russophilic vs Ukrainophilic divide that has endured for the first half of the 20th century.