Two possible leads for your question about /t/ as [r]. I'm not a Brit, so I'll defer to those with more knowledge. 1) If a final /t/ is dropped due to reduction, and a vowel-vowel sequence occurs, I assume an intrusive [r] could result. https://en.wikipedia.org/wiki/Linking_and_intrusive_R#IntrusiveR 2) In my youth, I watched movies that had characters with an upper class British accent in which an /r/ sounded like a [d] (but I know now that it was an alveolar tap [ɾ]). This tap is also the modern Spanish /r/ [ɾ]. Wikipedia states that "older Received Pronunciation" used the tap /r/ [ɾ]. https://en.wikipedia.org/wiki/Dental_and_alveolar_flaps

Hi - a British point I’d view, and bear in mind much of this is not about right or wrong, it’s about usage, which may change depending who you are talking to, or speed (for example). ‘To’ I’d say /də/ or /tə/ Into - usually silent, but not always, can be /intə/. Of - /ə/ in first example and either /də/ or /tə/ in second. Where I come from we wouldn’t pronounce /t/ as /r/ but I know some accents that may; such as a Liverpool accent.

I don't know IPA very well, but if (r) means a barely-voiced "r" sound ("r" as in "rain" / "rope" / "red"), then I would say no, "to" is never, as far as I'm aware, pronounced with the sound (r). Your first transcription, "ɡəʊ (d)ə hel," looks right to me. For "come into my house," I wouldn't say that the "t" is silent. It seems like more of a very soft "d" sound to me. I presume this would render something like "ɪn(d)ə" in IPA. Your third sentence looks good to me. I think you might get very different answers for all of these examples from people in different English-speaking regions, though. (I can't personally think of any dialect of English where "to" ever has any kind of "r" sound in it, though.)