That 「と」 must be written in hiragana because it is a particle. You have no choice here.

The 「と」 turns the preceding word 「コロッ」 into an adverb form so that it can modify the verb phrase 「[転]{ころ}がってたりする」.

「ころっ/コロッ」 is a colloquial and onomatopoeic "word"; therefore, it is not very important whether you write it in hiragana or katakana. You have a choice here. Your preference can be fully reflected in its orthography.

My own TL attempt for:

「コロッと[転]{ころ}がってたりするもんだ。」

would be:

"one might find (helpful things/items) lying about (unexpectedly)"

 

"(to your surprise) you may find (helpful things/items) just scattered about "

That 「と」 must be written in hiragana because it is a particle. You have no choice here.

The 「と」 turns the preceding word 「コロッ」 into an adverb form so that it can modify the verb phrase 「[転]{ころ}がってたりする」.

「ころっ/コロッ」 is a colloquial and onomatopoeic "word"; therefore, it is not very important whether you write it in hiragana or katakana. You have a choice here. Your preference can be fully reflected in its orthography.

My own TL attempt for:

「コロッと[転]{ころ}がってたりするもんだ。」

would be:

"one might find (helpful things/items) lying about (unexpectedly)"

"(to your surprise) you may find (helpful things/items) just scattered about "

That 「と」 must be written in hiragana because it is a particle. You have no choice here.

「ころっ/コロッ」 is a colloquial and onomatopoeic "word"; therefore, it is not very important whether you write it in hiragana or katakana. You have a choice here. Your preference can be fully reflected in its orthography.

My own TL attempt for:

「コロッと[転]{ころ}がってたりするもんだ。」

would be:

"one might find (helpful things/items) lying about (unexpectedly)"

"(to your surprise) you may find (helpful things/items) just scattered about "

That 「と」 must be written in hiragana because it is a particle. You have no choice here.

The 「と」 turns the preceding word 「コロッ」 into an adverb form so that it can modify the verb phrase 「[転]{ころ}がってたりする」.

「ころっ/コロッ」 is a colloquial and onomatopoeic "word"; therefore, it is not very important whether you write it in hiragana or katakana. You have a choice here. Your preference can be fully reflected in its orthography.

My own TL attempt for:

「コロッと[転]{ころ}がってたりするもんだ。」

would be:

"one might find (helpful things/items) lying about (unexpectedly)"

"(to your surprise) you may find (helpful things/items) just scattered about "